Answer:
3. I think you SHOULD go out more and meet new people:C
4.You DON'T HAVE TO come with us if you don't want to:A
5.This is a secret between you and me so we MUSTN'T tell anyone:B
Step-by-step explanation:
Just look and listen close to what the sentence says and pick what makes the most sense!
Hope my answer helped please have an amazing day today!