Synonym of INGENUOUS

Answer: Option B

Cunning : having or showing skill in achieving one's ends by deceit or evasion.
Frank : open, honest, and direct in speech or writing, especially when dealing with unpalatable matters.
Courteous : polite, respectful, or considerate in manner.
Clever : quick to understand, learn, and devise or apply ideas; intelligent.
Ingenuous : (of a person or action) innocent and unsuspecting.

Synonym of Ingenuous is Frank