Why are we assuming Maricella plays golf because Shigeru plays golf.

@sarahanthony, happy to help. Rule #4 says: "If Maricella plays tennis, then Shigeru plays tennis." We can diagram this as: M(t) -> S(t) The contrapositive of this is S(g) -> M(g). This allows us to deduce that Maricella has to play golf if Shigeru plays golf, which is the case in this question. Does that make sense? Please let us know if you have any other questions!

Yes, that helps. Thank you

I have the same question as mentioned above, but I am still not understanding how S(g)-> M(g) is the contrapositive of M(t) -> S(t)... ? Please explain!?

If M is playing tennis, then s must also play tennis. The question stem says S is playing golf, therefore according to the rules s CANNOT be playing tennis, or else you'd be breaking rule #4.