？
What business is it of yours what anyone's hobbies are?
Literal
Who [subject-が] what-kind-of hobby [copula-だろう] [even-と] your [genitive-の] known thing [question-か]?
A rhetorical dismissal. 誰がどんな趣味だろうと ('no matter who has what hobby') uses the concessive [question word] + だろうと ('whatever X'). 君の知ったことか ('what's it to you,' literally 'is it a thing you know?') is a fixed rhetorical phrase used to tell someone to mind their own business. The whole utterance is confrontational and dismissive — 'butt out.'