Concept:Sentence sequencing based on cause-and-effect links between the fixed opening S1 and closing S6.
Explanation:S1 states that Britain was the first country to experience modern industrialisation.
The next sentence must say why Britain could industrialise first.
Q provides the foundational reason: Britain had been politically stable since the seventeenth century under a unified monarchy.
P explains the result of this stability — common laws, a single currency, and a market not fragmented by local taxes.
This unified economic system leads naturally to R, which says money was widely used as a medium of exchange by the end of the seventeenth century.
S directly follows R because it states the consequence of a money-based economy: many people received income as wages and salaries instead of goods.
Finally, S6 explains the outcome of wage income — wider spending choices and an expanded market for goods.
Thus, the correct logical sequence is Q, P, R, S.
Answer:A. QPRS