In a country with a birth rate of 42 per 1,000 and a death rate of 17 per 1,000, the rate of natural increase is

The rate of natural increase is obtained by subtracting the crude death rate from the crude birth rate: 42 − 17 = 25 per 1,000. Option A is merely the death rate, option C is merely the birth rate, and option D is the sum of both rates, which is a common error.