FIRST DIGIT of each number and dividing by three we get574 → 474 ÷ 3 = 158658 → 558 ÷ 3 = 186821 → 721 ÷ 3 = 240.33945 → 845 ÷ 3 = 281.67247 → 147 ÷ 3 = 49There are three such number which are DIVISIBLE by three.Hence, "Three" is the correct ANSWER.