Someone answer my questions i need them asap

The process of? involves students offering each other constructive feedback to improve their written drafts.

2. discuss some major differences between the satellites present with each planet.

Which is the best way, if any, to rewrite sentence (3)? a) leave as is. b) her childhood was normal, filled with friends, activities, and fun. c) her childhood was normal, filled with friends, doing activities, and fun. d) her childhood was normal, filled with friends, doing activities, and having fun.