What would be the best degree classification to accept?

[youarenotkiddingme]

I've completed degree over many years.
LP of disabled child and not done as well as I'd expect (did extremely well on some modules).
Not done as well as I'd have liked and embarrassed disappointed.

Financially not in position to do more right now.

So choice is to accept one of following

A) BSc open degree
B) BSc (Hons) open third
C) BA open degree
D) BA (hons) open third

Is there option to upgrade a degree to honours at a later date when finances available?
I know I can do post grad modules when finances allow which will look better.

Which one should I accept?

BSc Open Degree. BScs are often thought of as being slightly harder than BAs

I'd choose BSc Open Degree, though you may still be asked for the clarification (third) when you apply for jobs etc.

Congratulations, completing a degree is still a massive achievement.

Would you take just the degree or hons and a 3rd classification?

BSc (Hons) open third.

It is better to have the "Hons". If you didn't have it I would assume you achieved a pass degree which is lower than a third. One girl in my year got this and so could not graduate with honours.
As pp said BSc is often considered to be more difficult than a BA.

Well done on completing your degree.