Which one of the following is similar in meaning to the word 'maxim' as used in the passage?

A 'maxim' is a short statement expressing a general truth or rule of conduct, which is essentially a principle. 'Necessity is the mother of invention' is a well-known principle/proverb about human behaviour. While direction, value, and observation are related concepts, 'principle' is the closest synonym for 'maxim' as a guiding rule or fundamental truth.