Consider a state 100 representing 001 as Q2 is the rightmost in figure. The FFs are triggered on rising edge (0-1). Ignoring the flip flop delays as it is asynchronous counter,
111 - next state 011, CLK1 changed from 1-0
011 - next state 101, CLK1 changed from 0-1, CLK2 changed from 1-0
101 - next state 001, CL1 changed from 1-0,
001 - next state 110, CLK1 changed from 0-1, CLK2 changed from 0-1
110 - next state 010, CLK1 changed from 1-0
010 - next state 100, CLK1 changed from 0-1, CLK2 changed from 1-0
100 - next state 000, CLK1 changed from 1-0
000 - next state 111, CLK1 changed from 0-1, CLK2 changed from 0-1
So, cycle repeats 7-6-5-4-3-2-1-0-7 mod 3 down counter.
So, A is the answer.