Select the most appropriate option to fill in the blank.

I think I have left ______ lunchbox at your house.

my

The most appropriate option to fill in the blank is my.

The word my is a possessive pronoun that refers to the speaker. In this case, the sentence is saying that I think I have left my lunchbox at your house. This means that the speaker is referring to their own lunchbox.

The other options are not correct.

• I does not make sense because it is not a possessive pronoun.
• Me does not make sense because it is not a possessive pronoun.
• Mine can be used, but it is less common than my in this context.