The correct option is B 4 and 7
The given series is: 9 3 4 5 9 3 5 9 3 6 4 3 9 3 3 5 3 9 5 3 9 3 7 5 7 5 9 3 9
Number of 4's: 9 3 4 5 9 3 5 9 3 6 4 3 9 3 3 5 3 9 5 3 9 3 7 5 7 5 9 3 9: 4's occur 2 times
Number of 7's: 9 3 4 5 9 3 5 9 3 6 4 3 9 3 3 5 3 9 5 3 9 3 7 5 7 5 9 3 9: 7's occur 2 times
Thus, number of 4's and 7's are same.