I would say that the tone was humorous
Answer: The professor's offer is an example of BENEVOLENT SEXISM.
Explanation: Benevolent sexism can be defined as the evaluations of a gender that may appear subjectively positive, but are actually damaging to people and gender equality more broadly.
It is a gesture for a gender that could be seen as positive but in actuallity, is damaging for gender equality because it reinforces the idea that the other gender needs help.
