The question is which one to choose.

Literal

Problem [topic-は], which [obj-を] if-chose good [Q-か] [quotative-という] thing [copula-だ].

~たらよいか is a standard construction for asking 'which should one do' — literally 'if one does X, would it be good?' どちら ('which of two') is the polite form of どっち.