What punctuation is used to introduce extended quotes that are longer than three lines?

commas

dashes

hyphens

colons

I believe that the correct option is: D) colons.

Extended quotations that are longer than three lines are introduced with a colon and then they start on a new line but having its entirety indented half an inch from the left margin.

For example:

Mary begins to talk about her past:

(this is where the quotation is)