The seven letters correspond to seven unique digits chosen from 0 to 9. The relation among the digits is such that:
P.Q.R = X.Y.Z = Q.A.Y

Q55. The value of A is:
A. 0
B. 2
C. 3
D. 6
E. None of the above

Q56. The sum of the digits which are not used is:
A. 8
B. 10
C. 14
D. 15
E. None of the above