Which phrase is an example of chiasmus?

Chiasmus is a rhetorical device in which the structure of words or phrases is inverted in two parallel segments. This technique often emphasizes a contrast or a deeper meaning through its structure.

The phrase "Ask not what your country can do for you, ask what you can do for your country." demonstrates chiasmus effectively. Here, the speaker flips the order in which the subject and action are presented, first focusing on the country’s role in relation to the individual, and then reversing that relationship to highlight the individual’s responsibility to the country. This inversion creates a memorable impact and encourages the listener to consider a more active role in civic responsibility.

The other phrases do not showcase this structural inversion. They do convey strong messages or themes but lack the specific overlapping construction characteristic of chiasmus, which makes the selected phrase the clear example of this rhetorical device.