The first two apropos commands return far too much information to be useful. The third command, apropos "copy file" returns a reasonable amount of information:
Macintosh:~ sample$ apropos "copy file" CpMac(1) - copy files preserving metadata and forks File::Copy(3pm) - Copy files or filehandles cp(1) - copy files cpio(1) - copy file archives in and out ditto(8) - copy files and directories to a destination directory
From that result, you might surmise that CpMac, cp, or ditto would be an appropriate tool for copying files. Of course, the manual entry for each command provides more helpful information.
The command man -k "copy file" is equivalent to apropos "copy file" and yields the same results as Exercise 1.