Your friend mentioned in question $4$ is having problems finding the bootmgr file and asks for your help. What is your best response?

a$.$ Use the File Explorer options applet to unhide the hidden bootmgr file.

b$.$ Explain to your friend that performing a startup repair is a better option.

c$.$ Use diskpart commands to "unhide" and locate the file.

d$.$ Explain to your friend that they can use the bootrec command to fix the bootmgr file without having to copy another file to the computer.