سوال ۲۱ کنکور ارشد علوم کامپیوتر ۱۳۹۸

Read the following excerpt from PASSAGE 2 and answer the question.

In comparison with facsimile, which has become very popular in recent years, electronic mail is more economical, has the flexibility advantages above, and is in principle more convenient for data already stored in a computer. Facsimile is far more convenient for data in hard-copy form (since the hard copy is fed directly into the facsimile machine). It appears clear, however, that the recent popularity of facsimile is due to the fact that it is relatively hassle-free, especially for the occasional or uninitiated user. Unfortunately, electronic mail, and more generally computer communication, despite all the talk about user friendliness, is full of hassles and pitfalls for the occasional or uninitiated user.

The popularity of facsimile is due to its ----------.