The sentence: (c.) The children enjoy climbing on the playground equipment, is a sentence that uses the word climbing as a gerund. That is because climbing is directly appointed or connected to the playground equipment. A gerund is a word that is in the form of verb but acting as a noun.
The Answer is A. Because B does not make sense when you say it out loud.
As the quantity supplied goes up, the price goes up, to increase profits. As the quantity goes down, the price stays high, to maintain profits. Eventually, if the quantity stays high, the price goes down to maintain sales.
Answer:
It's in Simple present tense...
hope it helps