For the reaction
`A + B to 2C + D` which of the following statements is/are correct?
A. Rate of disappearance of B = `1//2` x rate of appearance of C
B. Rate of disappearance of B =`1//2` x rate of appearance of C
C. Rate of disappearance of A = rate of appearance of B
D. Rate of disapperance of A = rate of disapperance of B.