Hi, I came across a grammar problem on which I got wrong and still can't figure out the reason. Please help!

A: Can you see my car from your office window?
B: Yes. __________ from a distance, it looks so tiny.

a) Seen
b) Seeing
c) Having seen
d) To be seeing

I initially chose 'b' and it turns out as incorrect and the correct answer is 'a'.
'd' is an obvious wrong answer and I eliminated it.
I chose 'b' because I understood as that B says "it looks so tiny" simultaneously as he is 'seeing' the car from a distance. I thought a) Seen and c) Having seen would be awkward answer choices. But it turns out 'a' is the answer and now my question is if 'a' is the answer, why can't 'c' be answer as well? Is there a subtle difference in the meaning due to the different tense of past participle and having+past participle? If so what exactly is it? Any help would be greatly appreciated!