A question about English grammar?

Question

I'm studying English. 

I have a question about English.

Which of the following sentences is natural?

1. 

A: Which bike is yours?

B: This red one is. 

2. 

A: Which bike is yours?

B: It's this red one. 

Thanks in advance. 

Answer 1

Both answers are quite normal.

If there is only one red bike visible, most of us would probably just say, "The red one". But if there were two or more red bikes, we would point at one of them and say "This red one".

Answer 2

They are both correct.  The most common response would be "The red one is", or simply "The red one".

@Anonymous:  Yahoo automatically adds a question mark. There is no way to post without a question mark.

Answer 3

Both are fine.

But "A question about English grammar" isn't a question.  It's a statement with a question mark at the end.

Answer 4

Both seem perfectly natural to me . 

Answer 5

I think it would be “the red one [is].”