Concept:Logical sequencing of a paragraph using pronoun references and thematic flow.
Explanation:S1 states Buddhism spread in the 5th–6th century.
P introduces the key role of monks in this process.
Q says “We know a little about some of them” – “them” refers to monks, so P must come before Q.
R gives background: Buddhism reached Sri Lanka earlier (time of Ashoka).
S introduces the monk Buddhaghosha traveling to Sri Lanka in the 5th century.
S6 begins with “He” (Buddhaghosha) and describes his work, so S must be immediately before S6.
Thus the correct order is P, Q, R, S — forming PQRS.
Only option 3 (PQRS) matches this sequence.
Answer:The proper sequence is PQRS (option 3).