The correct answer is A. (i) and (iii) only.
If the demand for a good is price elastic, a fall in its price will lead to a rise in sales and a rise in total expenditure on the good. This is because consumers are more sensitive to changes in price when demand is elastic. When the price of a good falls, consumers will buy more of it, which will lead to a rise in sales. In addition, the lower price will mean that consumers will spend more money on the good, which will lead to a rise in total expenditure.
Option (ii) is incorrect because a fall in price will lead to a rise in sales, not a fall in sales. Option (iii) is correct because a fall in price will lead to a rise in total expenditure, not a fall in total expenditure. Option (iv) is incorrect because a fall in price will lead to a rise in total expenditure, not a fall in total expenditure.