When is it appropriate to use a colon in a sentence?

question 19 options:

to summarize a paragraph

to join two dependent clauses together

to introduce a list

to join an independent and dependent clause together

Read the excerpt from chapter 6 of  animal farm.by the autumn the animals were tired but happy. they had had a hard year, and after the sale of part of the hay and corn, the stores of food for the winter were none too plentiful, but the windmill compensated for everything. it was almost half built now.how does the pacing of this passage affect the reader’s interpretation of the text? a flashback to earlier events provides a pause in the pacing to slow events down.foreshadowing of events provides information as to what will happen to the windmill.the pace of the text quickens to convey the characters’ resolve to finish the windmill.the pace of the text quickens to move the story to its climax, the completion of the windmill.

Ineed on this app i was at ambitious but then all of the sudden i got put back to about 30 points. is there something i can do about this, because i lost all of my progress in this app.

The room was gaudy with its leather couch and purple walls