Principles
I think principal is not right because it doesn’t look right.
I would say the first one
Answer:
it is the 3 one and number 2 contains a comma splice
Explanation:
2.The dress is a bit big on her; my mother has made it stay with pins
3.The dress is a bit big on her. My mother has made it stay with pins.
it is supposed to be The dress is a bit big for her. My mother has made it stay with pins.