Explanation:

Let’s break this down—

Here’s what happens if a Muslim man marries a fifth wife:

- Under traditional Muslim personal law, a man can have up to four wives at the same time.

- If he tries to marry a fifth, that marriage breaks the legal limit as per Islamic rules.

- Such a marriage isn’t just frowned upon, it’s straight-up void—as in, legally non-existent from the get-go. Not valid, not irregular. Null from day one.

- Option 1: Valid—Nope, the law is clear: not allowed.

- Option 2: Irregular (fasid)—Not really. Irregular marriages are those that can be fixed (maybe improper witnesses or waiting periods). Marrying a fifth wife, though, is an absolute bar. You can’t just fix it and make it fine.

- Option 3: Void— This is the correct answer. Completely illegal and has no legal effect.

- Option 4: Either (a) or (c)—That just makes no sense here.