According to this, the answer is A.
Know, because know is present tense as is the rest of the sentence.
In Shakespeare's time, a stage wasn't just one type of space; plays had to be versatile. The same play might be produced in an outdoor playhouse, an indoor theater, a royal palace—or, for a company on tour, the courtyard of an inn.
When the movie ends, what the oak tree does at the theater is that it leaves.
This is a pun supposed to have a humorous effect on the listener or the reader - usually, when a movie ends, people leave the theater. However, since this is a tree, and it's got leaves, you can understand the correlation between the two words.
