1.  DEF, HIJ, MNO, ?

A. STU
B. RST
C. RTV
D. SRQ
E. TUV

Answer: Option A

Explanation:

The letters in each term are consecutive.

There is a gap of one letter between the last letter of the first term and the first letter of the second term and a gap of two letters between the last letter of the second term and the first letter of third term.

So, there would be a gap of three letters between the last letter of the third term and the first letter of the fourth term.