Hence D is Option is correct.
- fanatic means a person filled with excessive and single-minded zeal, especially for an extreme religious or political cause.
- zealot means a person who is fanatical and uncompromising in pursuit of their religious, political, or other ideals
- maniac means a person exhibiting extremely wild or violent behaviour.
- rational is based on or in accordance with reason or logic, term used in mathematics .While others terms are non mathematical terms.