Section 13. Statements made by persons to Commission.

No statement made by a person in the course of giving evidence before the Commission or an officer or agency, referred to in clause (a), or the person appointed under clause (b), of sub-section (1) of section 12, shall subject him to, or be used against him in, any civil or criminal proceeding except a prosecution for giving false evidence by such statement : Provided that the statement,- (a) is made in reply to a question which is required by the Commission or such officer or agency or such person to answer, or (b) is relevant to the subject matter under investigation.