"Sentence" vs "A sentence"

[Tom]

Hi

Could you please tell me which one of the following sentences is correct?

1- A sentence is a group of words that give complete
meaning

2-Sentence is a group of words that give complete
meaning

3- The sentence is a group of words that give complete
meaning

Thanks a lot

Tom

[Yankee]

Hi Tom

I'd prefer the first sentence and would also change give to gives.

I would not use the second sentence (without an article).
Using the is possible, but as I said, I'd prefer a for your sentence.

Amy