Final answer:
Option A: Moore objects to the naturalistic fallacy because it confuses moral properties like 'good' with natural ones, a flawed reasoning he highlights with the open-question argument.
Step-by-step explanation:
G. E. Moore objects to the naturalistic fallacy because he claims that it confuses the 'good' with the 'natural.' In his book Principia Ethica, Moore explains that deriving moral properties, such as 'good' or 'right,' from natural properties commits the naturalistic fallacy.
Moore's critique is based on his open-question argument, which suggests that ethical terms remain open to questioning, unlike natural properties that can be empirically verified. The naturalistic fallacy erroneously tries to deduce what we ought to do from what is, an error in logic that Hume earlier identified as the is-ought problem. Moore argues that 'good' is a non-natural quality that cannot be equated with any natural property, making any such attempt circular and uninformative.