The critical path is A-B-C = 9 days. Activity D's early start is after A (day 3), but with start-to-start with B, it can start at the same time as B (day 3). D's late finish is determined by the critical path; D has float.
Need to compute: ES D = max(EF A=3, ES B=3) = 3; EF D = 5. Late start/end: Since D is not on critical path, its float is 9 - 5 = 4 days? Actually, need to consider dependencies: D's start-to-start with B means D can start when B starts. B starts at 3, so D starts at 3, ends at 5.
B is on critical path, so B's late start = 3. D's late start = 3 (because start-to-start), so D's late finish = 5. Total float = LS - ES = 0? That would make D critical? Wait, need to analyze properly: With start-to-start, D's start is tied to B's start.
B is on critical path, so B's late start = 3. D's late start = 3, so float = 0. So D is also critical? But D is not on the critical path originally.
Actually, if there is a start-to-start with B, then any delay in B delays D, but D's own duration is separate. The critical path is the longest path. Path A-B-C = 9.
Path A-D? D has no successor? Actually, D finishes, then what? No successor mentioned, so D's path length = 3+2=5. So not critical. But with start-to-start, D's early start is constrained by B, but B's early start is 3.
So D's early start = 3. D's late finish? Since D is not on critical path, its late finish can be 9? But if D finishes later than 9, it might not delay project if no successor? But without successor, D's late finish is project end. So D has float.
The float is 9 - 5 = 4. So statement about float: D has 4 days total float.