I -/have/had never thought of that

Hello, I am currently a bit confused about the difference between these 3 phrases:

1. I have never thought of that. (present perfect)

2. I had never thought of that. (past perfect)

3. I never thought of that. (past simple)

Imagine this situation: Someone has just told me they are going to London next week. They ask me if I ever want to visit that city as well.

(an unlikely situation I know, but it's just an expemplary one so take that in consideration, please)

What tense would I use as my reply? 1., 2. or 3. ?

Thanks for any help.