A. is no good - there are few if any cadetships around at the moment, and that's not going to change any time soon.
C. seems like a waste of a year. You're going to have to fund your ATPL(f), so why wait? There aren't many careers where a Masters gets you much more money than a Bachelors degree.
So that leaves B. Yes, you might be putting effort into a career that's leading nowhere - but you're going to have to fund your training somehow, and that will involve working. You have to do B. eventually, so now's a good time to do it.
Good luck!
FFF
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