Explanation:

- Let's assume the original price of salt per kg is Rs "x".

- With a 15% reduction, the price becomes Rs 0.85x per kg.

- The person buys 2 kg more salt for Rs 72 due to this price drop.

- So, Rs 72 can buy \(\frac{72}{0.85x} = n + 2\) kg where n is the original kg they could buy at price x.

- Originally, for Rs 72, they can buy \(\frac{72}{x} = n\) kg.

- Solving: \(\frac{72}{0.85x} - \frac{72}{x} = 2\)

- Solving this equation gives x = Rs 24.

- Reduced price = 0.85 * 24 = Rs 20.40.

- Correct answer: Option: 1, 20.40