If your coworker is making a quick private call, you should a. ignore them, so you can concentrate on your work b. listen carefully, so you can tell others what you hear c. report them to your supervisor, so they can be punished d. make your own phone call, so they see how it feels

The correct answer is

A) Ignore them, so you can concentrate on your work

It is not good to interrupt someone privacy. It might be an important and urgent call. There might be an emergency and making call be compulsory so if someone is making a private call, it is not a good habit to interrupt him and bother him. Making own work efficient and concentration is far better than  taking others matters into consideration.

none because it's so obvious

which functions return a valid value without any arguments?

(-blank- and -blank- return a valid value without any arguments.)

1st -blank-

today

sqrt

count

2nd -blank-

round

now

sqrt