Q. Find out the next group of letters in the following series.
STMJ, PQNL, MNON, JKPP ____
Take the first letter of each group and compare their place values:
S P M J G
19 16 13 10 7 (Difference of 3)
Now compare the place values of the last letters in each group:
J L N P R
10 12 14 16 18 (Addition of 2)
The first letter G and the last letter R are given in choice B.