One who knows two languages:

The correct answer is C. Bilingual.

A bigot is a person who is intolerant of other people’s opinions or beliefs. Bigamy is the act of being married to two people at the same time. Brittle is something that is easily broken or damaged.

A bilingual person is someone who can speak two languages fluently. They may have learned both languages as a child or they may have learned one language later in life. Bilingual people often have an easier time learning other languages and they may also have an advantage in their careers.