Questions

Demand is said to be inelastic, when the demand for the good doesn't change much or it is negotiable when the price of the good changed.

TON is the word which is the unit of weight. In forward it has weight of 1000 kgs and in backwords NOT which has no weight.

Sound waves cannot be transmitted through vacuum. 

Since, the starting statement carries a subject; the next statement will carry a verb i.e. Q follows as it mentioned the discovery of the Regent. R will bethe continuing statement which states what he actually discovered. P follows next as it talked about the reaction of the Regent after the discovery. And S would be the concluding statement and thus form a coherent paragraph.

The correct formation would be, ‘The Regent having discovered that he had imprisoned an innocent man released Voltaire and gave him a pension.’