Final answer:
The answer to the riddle is B) Breath, as it refers to human capability and not the actual weight of an object. The strongest man can't hold his breath for much longer than two minutes, which confirms that the answer is based on the limits of human endurance rather than the physical weight of objects.
Step-by-step explanation:
The riddle posed by the student, "What is as light as a feather, but even the strongest man can't hold for more than two minutes?" has an answer that is not directly related to weight but rather to human capability. The correct answer is B) Breath. Despite being intangible and lightweight, holding one's breath is a challenge regardless of a person's strength, and after a short while, the body's need for oxygen makes it impossible to hold a breath for an extended period. In contrast, the weight and physical properties of a cloud, a helium balloon, or a feather, do not correlate with the riddle since they can either float on their own or be easily held if not acted upon by external forces such as air resistance. Apollo 15 astronaut David Scott's demonstration on the Moon with a hammer and feather showcases the principles of physics and gravity in a vacuum where there is no air resistance.