6. Statements made by persons to the Commission
No statement made by a person in the course of giving evidence before the Commission 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 he is required by the Commission to answer, or
(b)
is relevant to the subject matter of the inquiry