The way I executed the function was that I used 5 drop-down menus for each argument.
"Create a function of your choice. The function must accept 5 arguments. Create a form that accepts 5 arguments, each via a drop-down menu, and echo the results back to the user."
Can you please confirm if it is just 1 drop-down menu like you replied where it is a multiple selection that selects 5 options simultaneously, or 5 drop-down menus where each drop-down menu selects 1 option and then passes it to the function? Does it matter how we do it?
if we are discussing the same questions (function.php) then
that is not how the question reads
The function must accept 5 arguments
Create a form that accepts 5 arguments, each via a drop-down menu.
says to me you need 1 drop down for each argument so at least 5....
they will have multiple options per dropdown (obviously)
but need 5