If a Husband compares his wife with his real sister, this form of divorce is called:

Option A is correct. Zihar is a form of divorce in Islamic (Muslim Personal) law where the husband makes a comparison between his wife and a female relative within prohibited degrees (such as mother or sister). This comparison, if intended, creates an irrevocable divorce. Khula is divorce at wife's instance, Illa involves conditional swearing, and Mubarrah is mutual divorce.