COF-C03 Account Management and Data Governance Practice Question
A data governance lead is configuring tag-based masking so that columns tagged with a PII classification are automatically protected. The lead creates a tag named PII_CLASSIFICATION and a masking policy, then applies the tag to several columns. Later, an analyst queries a tagged column and sees unmasked values. The masking policy was attached to the tag using ALTER TAG ... SET MASKING POLICY. What is the most likely cause?
⚠ Common exam trap
The trap here is assuming that associating a masking policy with a tag automatically protects every column, when the tag must still be applied to each column individually.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The masking policy was attached to the tag but the tag was not applied to the specific column at the column level.
Tag-based masking requires two conditions to be satisfied: the masking policy must be associated with the tag, and the tag must be applied to the target column. If the tag was only created or applied at the table level rather than the column level, Snowflake has no tagged column to protect, so queries return the original values. Verifying the column's tag assignment resolves the issue.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The masking policy was attached to the tag but the tag was not applied to the specific column at the column level.
Why this is correct
Tag-based masking only takes effect on columns that actually carry the tag. Creating the tag and associating the masking policy with the tag is not sufficient; the tag must be set on each column, for example with ALTER TABLE ... MODIFY COLUMN ... SET TAG. If the tag was applied only to the table or never set on the column, queries against that column return unmasked data, which matches the observed behavior.
- ✗
Tag-based masking requires the tag to be a system tag rather than a user-defined tag.
Why it's wrong here
Snowflake supports both system tags and user-defined tags for tag-based masking. A user-defined tag such as PII_CLASSIFICATION is valid for this purpose as long as the masking policy is associated with it and the tag is applied to the column. Requiring a system tag would make custom governance classifications impossible, which is not how the feature works.
- ✗
The masking policy must be attached to the tag before the tag is created on the column, and the order was reversed.
Why it's wrong here
The sequence of creating the tag, associating the masking policy, and setting the tag on a column is flexible in Snowflake. What matters is the end state: the tag has an associated masking policy and the column carries the tag. Reversing the order does not prevent enforcement, so this does not explain why the analyst sees unmasked values.
- ✗
The analyst's role has the ACCOUNTADMIN role granted, which bypasses all masking policies.
Why it's wrong here
Snowflake masking policies are enforced for all roles, including ACCOUNTADMIN, when the policy is correctly attached to a column or tag. While ACCOUNTADMIN can modify or drop policies, it does not bypass masking during query execution. The presence of ACCOUNTADMIN would not explain why a properly tagged and masked column returns unmasked values.
Visual reference
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Snowflake exam blueprint
This COF-C03 practice question is part of Courseiva's free Snowflake certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the COF-C03 exam.