Which of the following sentences contains a plural spelling error?

She had to use crutchs for several weeks after breaking her leg.
He was used to practicing on many different types of pianos.
The cashier collected the monies and deposited them.
We all tried to find the keys but had no luck at all.

Question

Which of the following sentences contains a plural spelling error?

She had to use crutchs for several weeks after breaking her leg.
 He was used to practicing on many different types of pianos.
 The cashier collected the monies and deposited them.
 We all tried to find the keys but had no luck at all.

ramen · Answer

what do you know so far about plural spelling?

ramen · Answer

we know so far that the words that can be plural are crutch, leg, piano, cashier, money, key