In the given sentence the subject and the object of the verb is 'she'. So a reflexive pronoun must be used.
The reflexive pronoun for singular third person is 'himself','herself' or 'itself' according to the gender of the noun. As the subject of the given sentence is female, the reflexive pronoun 'herself' must be used. Thus option B is the correct answer. Option A is incorrect.
'Him' and 'hers' are not reflexive pronouns. Thus options C and D are incorrect.