The correct answer is B

Explanation

The number of positive integer multiples of 3 that are less than or equal to 100 is 99÷3=33. The number of positive integer multiples of 5 that are less than or equal to 100 is 100÷5=20. The multiples of both 3 and 5 are the multiples of 3×5=15, and there are 90÷15=6 positive integers less than 100 that are multiples of 15. The multiples of both 3 and 5 are counted twice when counts of the multiples of 3 and the multiples of 5 are added together, so the number of positive integers less than or equal to 100 that are multiples of 3 or multiples of 5 or multiples of both 3 and 5 is 33+20-6=47.