Which of the following is a key purpose of Section 11 of the Public Gambling Act, 1867?

Section 11 indemnifies a person concerned in gaming who, when examined as a witness, makes a "true and faithful discovery" of all things on which he is examined. In return he receives a certificate and is freed from prosecution under the Act for what he did earlier in respect of that gaming, so the law buys evidence against others with immunity. Compelling persons found in a gaming-house to give evidence is the work of section 10, not section 11.