Since M only goes once, all of the other variables must occur twice to fill the game. Considering we cannot place P on Saturday, the other two Ps must be placed in Thursday and Friday. Which is the answer choice D.
As for answer choice B, there is no reason why M couldn't be placed on Thursday if we wanted it to. The group would fill up with M, L, and P.
I hope this helps. Please let me know if you have any other questions.