How many are there in Sonya's family?

1. There are four in her family:her father, mother, her little sister and her.

2. There are four in her family:her father, mother, her little sister and she.

3. There are four in her family:her father, mother, her little sister and herself.

4.There are four in her family:her father, mother, her little sister and Sonya.
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Which answers are correct?

#2 will be correct when you put a space after the colon!

A comma after "sister" is a good idea, too.

=)

Thank you. Are all the answers correct? Do we have to use 'she' or 'her' at the end?

Only #2 is correct.

Yes, you need "she" in that construction rather than "her" or "herself" or "Sonya."

All of the answers are correct. They all provide the same information and indicate that there are four people in Sonya's family. The only difference is the way pronouns are used to refer to Sonya herself.