$$A + H_{2}O \rightarrow B + HCl$$
$$B + H_{2}O \rightarrow C + HCl$$
Compound (A), (B) and (C) will be respectively:
A
$$PCl_{5}, POCdl_{3}, H_{3}PO_{3}$$
B
$$PCl_{5}, POCl_{3}, H_{3}PO_{4}$$
C
$$SOCl_{2}, POCl_{2}, H_{3}PO_{3}$$
D
$$PCl_{3}, POCl_{3}, H_{3}PO_{4}$$
Correct option is B. $$PCl_{5}, POCl_{3}, H_{3}PO_{4}$$
$$\underset{(A)}{PCl_{5}} + H_{2}O \rightarrow \underset{(B)}{POCl_{3}} + 2HCl$$
$$\underset{(B)}{POCl_{3}} + 3H_{2}O \rightarrow \underset{(C)}{H_{3}PO_{4}} + 3HCl$$
Hence, Option "B" is the correct answer.