Explanation:

Let’s break it down:

- The law (Section 82, IPC) says that nothing is an offence if done by a child under 7 years old—they can’t be held criminally responsible.

- Option 1: 100-years-old man—The law applies equally to adults. Age, unless extreme mental incapacity, doesn’t excuse offenses.

- Option 2: 6-years-old boy— This fits perfectly. At 6 years old, a child isn’t legally responsible for a crime in India.

- Option 3: 12-year-old girl—At 12, a child may not always be responsible, but generally, over 7 years, criminal responsibility can apply (with exceptions between ages 7-12 based on maturity).

- Option 4: 18-year-old girl—This is adulthood. She’s fully responsible for her actions under criminal law.

Your answer: Option 2 is right for this legal principle.