And tend to be frequently misinterpreted in computer-mediated communication.
a.
sarcasm; criticism
b.
body language; sarcasm
c.
body language; criticism
d.
syntax; nonverbal messages

The answer is: A. Sarcasm; criticism

In a computer-mediated communication, we cannot see the expression and the tone that is used by the people we're communicating with.

This means that when those people use sarcasm or criticism in the form of text, it can be much more likely to be misinterpreted as a hostile attack.

protectionism fosters competition and keeps price regulated is not an argument in favor of protectionism.