Answer:
A. a longer life expectancy for patients
Step-by-step explanation:
So better healthcare means more effective medicines for diseases and everything, raising the life expectancy by a lot. better medicine cures diseases and helps disease numbers go down, but it doesn't completely get rid of them, so B. is wrong. C. is too specific, yes, technically if you live longer, the doctors have a longer career, but A. is a better answer. And D. just doesn't really make sense, all the research and more advanced healthcare needs to be funded by something, so if anything, the costs would go up.
hope this helps:)