Which one of the following gestures is interpreted as unfriendly ?

Staring is the answer. A fixed, prolonged stare at a person is read across most cultures as hostile, intimidating or rude, because it signals judgment or challenge. The gesture crosses the line from attention into intrusion.

Why the others fail:

• Holding someone's hand signals warmth, reassurance or friendship, and in Indian social settings it is ordinary between friends and family.
• Eye contact in moderation shows attention and sincerity. It becomes uncomfortable only when prolonged, which is exactly where it turns into staring.
• Smiling is the most widely understood friendly gesture and is used to build rapport.

The core concept is nonverbal communication. It links to GS Paper IV through empathy and emotional intelligence. An officer handling public grievances must read body language accurately and avoid appearing threatening.

Trap: many candidates pick Eye contact because it is called rude in some cultures. The exam tests the difference between normal eye contact and a prolonged stare. The question asks for the gesture that is unfriendly by default.