Statements made by persons to Commission.

No statement made by a person in the course of giving evidence before the Commission or any officer or agency or the person referred to in sub-section (1) of section 10, 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.