$A=\{b\}$

$B\frac{?}{\frac{?}{?}}=\{c,d\}$

Select the the expression that is an element of $P(AB).$ Elements of the Cartesian product are expressed as strings, andnot $\frac{\frac{?}{?}}{\text{;}}n-$tuples.

a$.(bc,bd)$

b$.\frac{\frac{?}{?}}{bc,bd}$

c$.\frac{\frac{?}{?}}{b,c}$

d$.(b,c)$