The correct answer is Option B:

Solution:
Considering the given options.

Option A.   

Option B.

On Option B:  Considering the given number pattern.

Here, the numbers are increasing.
So, we first find the rule.

Note that:
12 + 6 = 18
18 + 6 = 24
24 + 6 = 30
30 + 6 = 36

So, the rule is "add 6", and this is the required answer.

Hence, the correct counting pattern with the rule ‘add six’ is Option B: