Which sentence contains an incorrect possessive form?

Ahis solution took everybody's objections into account.
Bthe credit for the decorations is all hers'.
Cit looks as though that calf has wandered away from its mother.
Dsomeone's bike is in the driveway.

Verified Answer :

DBecause it's not saying who's bike it is

Answer:

b. The credit for the decorations is all hers'.

Explanation:

The correct possessive pronoun would be hers.

You don't need the apostrophe (') with possessive pronouns.  

Possessive pronouns are mine; yours (singular); his; hers; its; ours; yours (plural); theirs. They are all used without the apostrophe (').