The correct option is
B R
It follows a pattern,
Sum of (position of alphabets in alphabetical series) is divided by 4 in 3,8 and 11 times respectively.
i.e. for 1st column
6+1+5=12,
2nd column
9+10+13=32,
3rd column
15+11+18=44 are divided by 4.
Hence R replaces question mark.