Answer: Option B
:
B
The above sequence can be split into two sequences, one having numbers and another having alphabets:
The number pattern is as follows:

So, the next term in the above pattern is 22.
The sequence of the alphabets is:
F, E, D, C
We observe that the alphabets are in reverse alphabetical order.
Sothe next term in the sequence of alphabets is B.
So, the next term in the sequence is 22 B.
So, the sequence becomes12 F, 13 E, 15 D, 18 C, 22 B.