Comprehensive and Detailed Explanation From Exact Extract:

wc -l counts the number of lines of input provided to it, which is commonly used to count the number of files when used with ls -l (excluding the header line). For example, ls -l /opt/application/home/ | wc -l gives the total count of lines, which corresponds to the number of files and directories (including the total line at the top).

Other options:

A. less is a pager utility.

B. tail -f shows the end of a file in real time.

C. tr -c translates or deletes characters, not for counting lines.