Compound A reacts with $PCl_5$ to give B which on treatment with $KCN$ followed by hydrolysis gave propanoic acid. What is A and B respectively ?

Question

( A ) $C_2H_6$ and $C_3H_7Cl$
( B ) $C_2H_6$ and $C_2H_5Cl$
( C ) $C_2H_5Cl$ and $C_2H_5Cl_2$
( D ) $C_2H_5OH$ and $C_2H_5Cl$