Phone calls are:.
A) incapable of conveying nonverbal signals.
B) only acceptable for external communication.
C) capable of offering the give-and-take of in-person conversations.
D) no longer practical due to IM and texting. E) preferable to electronic media when you need a permanent record.

The correct answer is letter "C": capable of offering the give-and-take of in-person conversations.

Explanation:

While talking about channels of communication, phone calls are useful to imitate the closest possible to face-to-face communication, with its limitations. The transmission of information is done in real-time and the participants can provide their points of view just as if they were talking in person.  

Though, expressions cannot be captured. Many people over the phone can pretend to have a mood modulating their tone of voice even if their feelings are opposite.

answer; automated fingerprint;

answer; lags, push the econ below the natural level of output;