The examples below are almost exactly the same, except for using a different future tense. Oh, is that the doorbell? Don’t worry; I’ll answer it. Oh, is that the doorbell? Don’t worry; I’m going to answer it. Which of the following is true?

Example 1 is correct but doesn’t make sense, and example 2 is incorrect or unnatural.

Only example 2 is correct and makes sense, as there is strong present evidence.

Only example 1 is correct and makes sense, as it’s a quick decision.

Both are correct and make sense as predictions, so we can use either will or (be) going to.