For a database relation R(a,b,c,d) where the domains ofa, b, c and d include only atomic values, only the following functional dependencies and those that can be inferred from them hold
$$a \rightarrow c$$
$$b \rightarrow d$$
The relation is in

A

First normal form but not in second normal form

B

Second normal form but not in third normal form

C

Third normal form

D

None of the above