Explanation:

- Let’s look at the options:

- Option 1: Hyderabad

- No referendum was held in Hyderabad for accession. The state was annexed through “Operation Polo” by the Indian army after the Nizam resisted joining India.

- Option 2: Junagadh and Hyderabad

- Junagadh had a referendum, but Hyderabad did not.

- Option 3: Bhopal

- Bhopal joined India, but not through a referendum.

- Option 4: Junagadh

- Junagadh saw a referendum after the Nawab wanted to join Pakistan. The people overwhelmingly voted to join India.

- So, Junagadh is the correct answer.