In which sentence is a colon used correctly?

to avoid unnecessary repetition, not every chapter has a map exercise attached. write a one or two-sentence answer explaining the significance of the items 7, ¶ 3-4 - civilization began in the fertile crescent because villages needed careful “in an epic tale told not long after his reign, we find gilgamesh claiming

in my opinion, anyone should be allowed to marry as long as it's not going against any laws. though i kind of contradict myself because i know that in some states and countries, gay marriage isn't legal yet- hopefully you get my point.