Verified Answer :

taskmasters
CI found a bag of marbles.

This is the only sentence that contains an indefinite article. Indefinite articles are "a" and "an" for singular nouns. "some" is the indefinite article used for plural or uncountable nouns.

"the" is a definite article.
Billymkhoi

There are only two indefinite articles known in English: "a" and "an". Therefore, the correct answer is c. I found a bag of marbles.

"The", however, is a definite article.

Hope this helps~