Typing in red a. is interpreted as yelling or anger b. is a good way to catch your readers attention c. to emphasize important points d. is essential when writing emails

I would say that typing in red is A) Is interpreted as yelling or anger. I say this answer because the color itself is associated with anger, like the saying "I saw red". It is used when angry.

D. is essential when writing e-mails

classical republicanism, also known as civic humanism, is a form of republicanism  developed in the renaissance inspired by the governmental forms and writings of  classical  antiquity, especially such  classical  writers as aristotle, polybius, and cicero.

on these days , humidity is very f.) high