Explanation:

- The Indian Penal Code (IPC) was enacted in 1860.

- Option 1: 1st June, 1860

- This is the date the IPC was enacted (passed).

- However, it is not the date it came into force.

- Option 2: 1st August, 1860

- Nothing significant related to IPC occurred on this date.

- Option 3: 6th October, 1860

- IPC was neither enacted nor enforced on this date.

- Option 4: None of the above.

- This option covers if none of the other dates are correct.

- The correct answer is: Option 1: 1st June, 1860

- The IPC came into effect from 1st January, 1862 in British India, but was enacted on 1st June, 1860.

- 6th October, 1860 does not have any legal connection to the IPC.