Humans cannot breathe underwater because our lungs donot have enough surface area to absorb enough oxygen from water, and the lining in our lungs is adapted to handle air rather thanwater. 

And Asphyxiation, also known as suffocation, means to die from lack of oxygen.

Hence, there may be the Lungs put in water be settled down so that it didn't get enough oxygen.

So answer is A.

Possible response:

Postmortem Evidence of Asphyxiation in a Child

Asphyxiation is a condition where the body is deprived of oxygen, leading to suffocation and potential death. When investigating a case of suspected asphyxiation, postmortem examination can provide valuable evidence to confirm or refute this hypothesis. One such method is the lung flotation test, which involves placing a piece of lung tissue in water and observing its behavior. Here are the possible outcomes of this test and their interpretation:

Settled Down
If the lung tissue sinks to the bottom of the water container, it suggests that the lungs were not inflated with air at the time of death. This could be due to drowning, poisoning, or other causes of respiratory failure. However, it does not necessarily indicate asphyxiation, as some external factors can also affect lung buoyancy, such as tissue degeneration, temperature, and fluid accumulation.

Kept Floating
If the lung tissue floats on the surface of the water, it suggests that the lungs were inflated with air at the time of death. This could be due to various causes, such as carbon monoxide poisoning, drug overdose, or suffocation by a gas or smoke. Asphyxiation by mechanical means, such as strangulation, hanging, or smothering, may also result in lung inflation, but the specific patterns of injury and hemorrhage would be different from other causes.

Had Blood Spots
If the lung tissue shows red or pink spots on its surface or edges, it suggests that the blood vessels in the lungs ruptured due to increased pressure or lack of oxygen. This is a sign of severe respiratory distress, which can occur in various forms of asphyxiation, such as choking, chest compression, or inhalation of toxic fumes. The presence and distribution of blood spots can also help determine the mechanism of asphyxiation and the position of the victim at the time of death.

None of These
If the lung tissue does not show any significant changes in water, it does not necessarily rule out asphyxiation, but it also does not provide strong evidence for it. Other postmortem findings, such as petechiae (tiny bruises) in the eyes, mouth, or neck, or fractures in the hyoid bone (a small bone in the neck), may support the diagnosis of asphyxiation by manual or ligature strangulation. However, the absence of such findings does not exclude other causes of death, such as natural disease, trauma, or poisoning.

Conclusion

In summary, the lung flotation test can be a useful tool in determining the presence and type of asphyxiation in a child, but it should be interpreted in conjunction with other postmortem findings and the circumstances of the case. A forensic pathologist or medical examiner can provide a detailed report on the cause and manner of death based on a comprehensive examination of the body and the available evidence.