Explanation

This tests successive percentage changes, which multiply rather than add. A 40% increase followed by a 20% decrease gives a net factor of 1.40 × 0.80 = 1.12, i.e. a 12% net increase. The trap is option (c) 20%, from naively adding 40 - 20; but the 20% decrease applies to the already-increased salary, so it removes more than 20% of the original. On ₹100: up to ₹140, then down 20% to ₹112. Hence option (d).