Which sentence has an ERROR in a plural noun?

That end of the pool is four feet deep.

This game has two halves, not three periods.

The scouts baked twelve loafs of bread for the church festival.

Matteo lost two teeth in just one week.

it should be loaves instead of loafs

The scouts baked twelve loafs of bread for the church festival.

Explanation:

The plural form of the noun loaf is loaves. The reason is that nouns ending in - f have an irregular plural form: - ves. Other examples of nouns ending in - f with similar irregular plural forms are:

knife - knives

wife - wives

life - lives

The rest of the sentences contain correct irregular plural forms:

half - halves

foot - feet

tooth - teeth