When long labels are required, which of these commands can you use to improve readability of a worksheet?
a. merge & center
b. wrap text
c. conditional formatting
d. sort & filter
d is wrong answer just took the exam and had to retake it.

  B. Wrap Text

The apt option would be Wrap text.

Explanation:

This option allows the user to wrap the lengthy text in to number of lines so that it gets accommodated in the given size not extending length wise. Here only the breadth gets increased.

Merge & Center option will work only we want to club or combine two or more cells and center the text.  

Conditional formatting works well when we want to do the format with a desired condition and does not suit for handling lengthier text.

Sort & Filter is to extract the necessary data based on some condition. So this does not suit the given objective.

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