What is the ksh syntax to use vi commands for the shell history?

A.
set-o vi

B.
set-h vi

C.
set-hist vi

D.
export history=vi

Explanation:
To enter the Korn shell and set up a working environment…
ksh to start the Korn Shell
set-o vito use vi to edit the command line
set-o noclobber to prevent overwriting files with a >
PS1=’$PWD’ to change prompt to current directory