Explanation:

- Section 85 of IPC deals with acts performed by a person incapable of judgment due to intoxication involuntarily caused. It provides a defense if there's no intention or knowledge of the act.

- Section 86 of IPC addresses intoxication and crime, emphasizing that if a person is voluntarily intoxicated, he will be considered to have the same intention and knowledge as a sober person while committing the act.

- Section 87 of IPC relates to acts which are not intended and not causing harm, performed with the other person’s consent. It doesn't pertain directly to intoxication.

- Option 4 suggests both sections 85 and 86 cover intoxication as a defense.

The correct answer is Option 4: both (a) & (b).