Assume the demand for watermelons is downward sloping. a decrease in price from $3 per pound to $2 per pound
(a) could have been caused by an increase in supply.
(b) will cause an increase in supply.
(c) will cause a smaller quantity of watermelons to be demanded.
(d) will cause demand to decrease.
(e) will cause demand to increase.

(E) will cause demand to increase.

Explanation:

The demand has a downward sloping, so it decrease as more price.

Therefore if the price is lower, the demand will increase, not decrease.

More persons will demand watermelons as the price decrease. That's because at lower price more people can afford watermelons.

answer; is usually (less than) the socially optimal level of consumption;

i guess you could put raise the economic balance