Which of the following deals with section 377, I.P.C?

Voluntary sexual intercourse against the order of nature with any man, woman, or animal is an unnatural sexual offence (Section 377 I.P.C). Penetration is sufficient to constitute the offence. These offences are punishable with imprisonment for life or upto ten years and also with fine. Ref: The Essentials of Forensic Medicine and Toxicology, 27th edition, Page 363.