Go the way of all flesh means to die or disappear like all living things. The correct answer is this meaning because the expression is used figuratively, not only by its literal words.

Examples:

• Many ancient customs have gone the way of all flesh.
• In an HSC essay, Go the way of all flesh can express this meaning: to die or disappear like all living things.
• When this expression appears in a passage, connect Go the way of all flesh with the idea of to die or disappear like all living things.