Explanation:

- Section 511 of the Indian Penal Code deals with "Attempts to commit offences punishable with imprisonment for life or other imprisonment."

- It applies to all attempts to commit offences for which no separate provision exists.

- Attempt of riot is not separately provided elsewhere, so Section 511 applies.

- Attempt of theft is not provided separately, so Section 511 applies.

- Attempt of murder is specifically dealt with under Section 307 IPC, so Section 511 does not apply here.

- "None" is incorrect because at least one of the above is excluded.

Correct Answer: Option 2 - Attempt of murder