(A): Fertilization in mammales occurs in uterus.
(R) : The embryo get implanted before cleavage divisions.
A. If both (A) and (R) are true and (R ) is the correct explanation of (A)
B. If both (A) and (R) are true but (R ) is not the correct explanation of (A)
C. If (A) is true but (R) is true
D. If both (A) and (R) are false.