I am going to . . . . . . . . concert tomorrow. A. a B. an C. the D. no article

The correct answer is: D. no article

The word “concert” is a countable noun, which means it can be used with a number. In this case, the speaker is not specifying which concert they are going to, so they do not need to use an article.

If the speaker were specifying which concert they were going to, they would use an article. For example, they might say:

• I am going to the concert tomorrow. (If they are going to a specific concert that has already been mentioned.)
• I am going to a concert tomorrow. (If they are going to a general concert that has not been mentioned before.)

The article “a” is used before singular countable nouns that are not specific. The article “the” is used before singular countable nouns that are specific.