I've got two sentences:
And now I'll announce the winner of the competition.
And now I'm going to announce the winner of the competition.
In which sentence the structure is used more accurately? Are there any rules that would apply to this exact (or similar) situation?
I know the difference between will and going to in terms of spontaneous/planned actions, but I'm confused here.
Edit: This sentence is from an exercise used in an English Language Competition.
The question prompt was "Decide whether the sentences are grammatically correct and try to correct the ones that are not."
The sentence in the exercise went
And now I'll announce a winner of the competition.
and in the keys the corrected answer provided was
And now I'm going to announce the winner of the competition.