Answer:
a colon
Step-by-step explanation:
A colon is used in sentences where the author wishes to state the order of things. A semi colon which looks like the colon is used to set apart two independent sentences. In the sentence above, a colon is the right punctuation to use because the author states the order of important points.
Before he begins stating this order, he attaches a colon to show that a list is being made. Colons are used to distinguish lists, examples and quotes.