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

a. to join two dependent clauses together

b. to join an independent and dependent clause together

c. to introduce a list

d. to summarize a paragraph

Which best identifies the figurative language used in this passage? cannon to right of them, cannon to left of them, cannon in front of them volley’d and thunder’d; storm’d at with shot and shell, boldly they rode and well, into the jaws of death, into the mouth of hell rode the six hundred.