The New Oxford American Dictionary (NOAD) is a substantial revision of the Oxford Dictionary of English (ODE, which is a British English dictionary). ... ODE was revised for NOAD, with some spelling changes, new words found only in the US, and (rarely) some changes in the order of entries for the American market.
Is that all there is to the question?
I think it's be D or A. Personally I'd choose D. Hope this helps.
He has mixed feelings as he is probably tired of getting work and is being given more and becoming lazy
He’s happy as if he does well it will benefit him
