Fill in the blanks:
It’s ___________for an effective journalism of curiosity-driven research to be commercially______________.

The sentence suggests that effective journalism based on curiosity-driven research faces commercial challenges. The word "difficult" fits the first blank because sustaining such journalism is not easy. The word "viable" fits the second blank, as it implies financial or commercial sustainability, which is often challenging in this context."Impractical, profitable" does not fit because curiosity-driven journalism is not necessarily impractical, though it may be financially challenging."Effortless, sustainable" contradicts the meaning, as good journalism is rarely effortless."Rare, beneficial" does not accurately express the idea of commercial sustainability.Thus, "difficult, viable" is the most appropriate choice.