Arrange the following gases in increasing order of van der Waals constant 'a'
(A) Ar
(B) CH$$_4$$
(C) H$$_2$$O
(D) C$$_6$$H$$_6$$
Choose the correct option from the following.

A

D, C, B and A

B

B, C, D and A

C

C, D, B and A

D

A, B, C and D