The digital sum of a number is the sum of its digits. For how many of the positive integers 24-140 inclusive is the digital sum a multiple of 7?  Choose the correct choice from the following answers.
A) 7	B) 8	C) 14	D) 15	E) 20

Rationale: is there other way than just listing ? 25 34 43 52 59 61 68 70 77 86 95 106 115 124 133 15 ways . . d
Answer: D