1. 

In the following question, a letter series is given. Some of the letters of the series are missing. This missing letters are given in same order as one of the four/five alternatives below the series. Find out the correct alternative.

__ __r__ttp__ __s__ tp__ __ __s__ __ __
A. pqrssqtpqrtp
B. pqstrsqptrst
C. pqsqrsqrrtpq
D. None of these

Answer: Option C

Explanation:

Pattern of the series as shown below

The last letter of each previous block is moved to the beginning of the successive block.

Now, pqrst/tpqrs/stpqr/rstpq => pqsqrsqrrtpq

Hence, the missing letters are pqsqrsqrrtpq.