Count to a certain value first, and you will find that the values of A are 1, 7, 13, 19 ... all 6, and D is 4, 10, 16, and 6.
1 4
7 10
13 16
19 22
1+6(n- 1)4+6(n- 1
201/6 = 33.5,33x6+1=199,201-199 = 2, so it is C.
You got it?