Explanation:

- The man bought toffees at 3 for a rupee. This means each toffee costs 1/3 rupee.

- To gain 50%, he must sell them for a price 50% higher than his cost price.

- Cost price for each toffee = 1/3 rupee. Therefore, 50% of 1/3 = 1/6 rupee.

- Selling price for each toffee to include a 50% gain = 1/3 + 1/6 = 1/2 rupee.

- Therefore, for 1 rupee, he would sell 1 divided by 1/2 toffees, which equals 2 toffees per rupee.

- Option 4: 2 toffees is the correct choice.

Correct Answer: Option 4 - 2