Which word or words and punctuation corrects any errors in the sentence?

to make the dough, mix three cups of flour, one cup of water, one third cup of vegetable oil, and a pinch of salt.

a.
three-cups
b.
vegetable-oil
c.
there is no error in this sentence.
d.
one-third

The correct answer is letter D. One-third. The basic grammar rule in spelling out fractions should always have a hyphen. The words one and third separately mean differently. One connected by hyphen with the word third, creates a new word and different definition, meaning, a numerical quantity.