Hey there!
“Plus” means you’re basically adding and “of” means you’re multiplying.
Now let’s answer your question….
“A number” = n
“Plus” = +
1/4 = 1/4 because nothing’s wrong with it
“Of the number” = n
Thus, your answer should be:
n + 1/4n (Option A.)
Good luck on your assignment & enjoy your day!
~ Amphitrite1040:)