nationality: british or britain?

If you see this in a listening test, what would you fill in?


I am of british nationality.(Is it correct?)

I am a british/ I am british.(Are they the same?)

I would use a capital letter whichever I filled in.

Nationality: British.
I am of British nationality.
I am British. (‘I am a British’ is not correct)

Thank you.

What do you mean by this sentence? And why do you use past tense for the verb fill?

I mean that Britain and British should always begin with a capital letter. Your examples didn’t.

I used the future in the past: