It's a verb that has to have a ACTION and a SUBJECT is the sentence.
Answer:
The effect of Audrey's parents suing the city to integrate public parks was C. The city closed all of its parks.
Explanation:
The sentence directly after where it states that Audrey's parents sued the city states that the city closed all of its parks. Therefore, the cause is Audrey's parents suing the city, and the effect is the city closed all of its parks.
They're extremely important to those who follow them. They're also taught to the younger generations in hopes that they will continue.