Using the normal schedule, given Activity 3001 and the relationship with Activity 4001.

 Relationship Analysis:

Activity 4001 starts 15 days after Activity 3001 begins, based on their logical dependency (SS +15).

This indicates partial concurrency, as both activities overlap in execution.

 Evaluation of Other Options:

A: Incorrect, as the statement refers to Activity 5001, not 3001.

C: Incorrect, as Activity 4001 does not start before Activity 3001.

 Verification with PSP Guidelines:

PSP guidelines stress precise interpretation of activity relationships (Ref: PSP Study Guide, Chapter 2A: Logical Relationships and Lags).