Correct Answer: Lenient

Solution : The correct choice is the second option.

Explanation:
Stern refers to someone who is strict, firm, or uncompromising in their manner. Lenient, on the other hand, means being more permissive, gentle, or tolerant rather than strict or harsh. It contrasts with the idea of being stern by suggesting a more forgiving or relaxed approach.

The meanings of the other options are as follows:

• Flippant: This word means lacking seriousness or respect, often characterised by a casual or disrespectful attitude.
• Desolate: This word refers to a place that is deserted, bleak, or empty, lacking inhabitants or features that make it lively.
• Noxious: This word describes something harmful, poisonous, or unpleasant, often relating to gases, fumes, or substances that are toxic to living organisms.

Therefore, the correct answer is lenient.