Two things to keep in mind when you’re deciding whether to use formal or informal english are
a. the author and the audience
b. the reader and the location
c. the occasion and the audience
d. the opinion and the occasion

C. The occasion and the audience

Explanation:

Two things to keep in mind when you’re deciding whether to use formal or informal English are the occasion and the audience.

in "letter from a birmingham jail," king argues that there are four basic steps in any nonviolent campaign: "[c]ollection of the facts to determine whether injustices exist; negotiation; self purification; and direct action." finally, direct action is taken and acts such as boycotts and sit-ins are staged.

to show how the cables work.