Question

In which sentence is the underlined word an indefinite article?

A.
Our mail carrier left one package.

B.
The sky is clear today.

C.
I found a bag of marbles

(these are the one that are underlined)
(A is one)

(B is the)

(C is a)

Answer 1

For English there are only two known indefinite articles, and those are "a" and "an". So, the correct answer you are looking for is C. I found a bag of marbles

Good luck with your studies, I hope this helps!