I don't have brothers or sisters.

[tzfujimino]

Please help me.

a. I don't have any brothers or sisters.
b. I don't have brothers or sisters.
c. I don't have a brother or a sister.

a´Do you have any brothers?
b´Do you have brothers?
c´Do you have a brother?

I can't find any grammatical errors in these sentences above.
I can't tell the differences in meaning, either.
If they're all correct, do they mean the same?

Thank you.

[David L.]

Can you think of a situation where your response would be :
I don't have any brothers or sisters.

and where you would say instead :
c. I don't have a brother or a sister.

[tzfujimino]

Thank you, David.

<situation A>
Q:Do you have any brothers or sisters?
A:No, I don't have any brothers or sisters.(meaning I'm an "only child".)

<situation B>
Q:Do you have a brother or a sister?(meaning "which" do you have?)
A:I have a brother(a sister).

I can't think of situations where "I don't have a brother or a sister." might be
used.
However, I realized that there is a difference in meaning between "Do you have any brothers or sisters?" and "Do you have a brother or a sister?"

[David L.]

She: I come from a big family - there are 9 of us.
He: I don't have any brothers or sisters.

She: My sister and I are like best friends. We do everything together.
He: I envy you. I don't have a brother or a sister. (stress is placed on 'or')