B) A person crossing railways track when the gates are open.
c) A family in park.
d) Students waiting for bus in line.

The correct answer is option 'A', which states that a boy leaning out of the window of a moving car is at high risk of his life. This answer can be explained by considering the potential dangers and safety hazards associated with this situation.

1. Lack of physical support:
When a boy leans out of the window of a moving car, he is not supported by any physical structure or safety measures. This increases the risk of falling out of the car and getting seriously injured or even killed.

2. Impact of speed:
Moving cars can reach high speeds, especially on highways or open roads. The higher the speed, the greater the force of impact in case of an accident or sudden brakes. If the boy leans too far out of the window, he may be unable to react quickly enough to avoid collisions or obstacles.

3. Unpredictable road conditions:
Roads can have various unpredictable conditions such as potholes, uneven surfaces, or sudden bumps. If the boy is leaning out of the window, he may not be able to anticipate or react to these conditions, leading to accidents or injuries.

4. Lack of protection:
Unlike inside the car, being outside the window exposes the boy to many external factors. He is vulnerable to flying debris, branches, insects, or even other vehicles. Without any protective barrier, he is at a much higher risk of getting hit or injured by these objects.

5. Distractions and loss of balance:
Leaning out of the window can be distracting for the boy, diverting his attention from the road and surroundings. This can impair his ability to judge distances and react to potential dangers. Additionally, if he loses his balance while leaning out, he may fall out of the car or lose control, leading to accidents.

Overall, the combination of lack of physical support, impact of speed, unpredictable road conditions, lack of protection, distractions, and loss of balance make a boy leaning out of the window of a moving car highly susceptible to life-threatening risks. It is essential to educate children about the importance of staying inside the car and following safety guidelines to prevent such accidents.