Which of the following groups of letters when sequentially placed from left to right will complete the given series?
p_qqrrssppq_rrssppqqrrssppqqr_s_

Correct option is C

Given: p_qqrrssppq_rrssppqqrrssppqqr_s_
Logic: In these types of problems, we have put all the given options and the option which gives logical pattern of letters that is correct option.
By option (a): qprs
p q qqrrssppq p rrssppqqrrssppqqr r s s (Not a logical pattern)
By option (b): srqp
p s qqrrssppq r rrssppqqrrssppqqr q s p (Not a logical pattern)
By option (c): pqrs
p p qqrrss / ppq q rrss / ppqqrrss / ppqqr r s s ( Logical pattern)
By option (d): prpr
p p qqrrssppq r rrssppqqrrssppqqr p s r (Not a logical pattern)
Thus, correct option is (c).