Ask Your Instructor
The problem with tests, especially academic ones, is that only the test developer knows why they think a given answer is correct. In a school context, the only way to know for sure is to ask your instructor.
All the terms you can choose relate to how activities are measured, rather than defining how the two tasks interrelate ...
What’s the relationship between the test planning activity and the testing activity?
The answer should be:
C. Finish-to-Start (FS)
The test planning activity needs to finish, in order to start the testing activity. The highlighted test response might be wrong. It happens.