Correct option is A
Given:
18 : 324 : 5832 :: 36 : 1296 : ?
Solution:
The pattern followed here :

We can observe a pattern here:
18 x 18 = 324
324 x 18 = 5832
So, for the second part of the analogy:
36: 1296:?

36 x 36 = 1296
1296 x 36
= 46656
the number that can replace the question mark is 46656.