Explanation:

990/5*9 = 22 natural numbers are divisible by 5 and 9
Of them,3 are divisible by 7:45*7 = 315,2(45*7) = 630 and 3(45*7) = 945
22-3 = 19

19 natural numbers are divisible by 5 and 9 both but not by 7

Hence, option 2 is the correct answer.