Assertion (A): Placenta acts as a major endocrine organ. Reason (R): In mammals fetal components of the placenta derive initially from the chondroblast.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.