A--You know the person (Henry) and the topic (paying for a movie ticket).
B--You know the people (the twins) and the topic (plans for their party).
D--You know the person (my mother) and the topic (lost an earring).
BUT for C there is a very vague sentence that makes you question: what is it that they wouldn't enjoy? So it is C.
Answer:
Every day at 4 p.m., my brother and I send radio messages to Mars to communicate with aliens who live there.
Explanation: