I would start in the setup. We know that the latest that M could go is in the middle of the three time slots. We also know that the earliest G could go is in the middle of the three time slots. So from our setup, we can see that A is correct. I would also try to prioritize answer choices that deal with variables we know the most about. For example, we don't know much about the timing of S and P, so I would deprioritize C and look to others first.