Koel is the single producer of home air conditioners in its rural market. The firm's monthly demand is described by the equation P = 5000 5Q, where P is the price and Q is the quantity of units sold. Which of the following must be true of Koel?

An increase in price decreases the quantity sold.

It is a natural monopoly.

A decrease in price decreases the quantity sold.

Higher levels of output bring in increasingly lower total revenue if demand is elastic.

Maintaining the current price decreases the quantity sold over time.