The sum of all the positive factors of 84 which are multiples of 7, is:

Correct option is D

First, find the positive factors of 84 which are multiples of 7.
Prime factorization of 84 = 84=22×3×7
The factors of 84 that are multiples of 7 can be obtained by multiplying 7 with the remaining factors of 84.
The factors of 84 that are multiples of 7 are:
7×1=7
7×2=14
7×3=21
7×4=28
7×6=42
7×12=84
Therefore, the factors of 84 that are multiples of 7 are: 7, 14, 21, 28, 42, 84.
Sum of these factors = 7+14+21+28+42+84=196
Hence, the correct answer is (d) 196.