Final answer:
The answer to the riddle 'What is it that you cannot hold even for ten minutes, even though it is lighter than a feather?' is d) Sunshine, because sunshine, while intangible and light, cannot be physically held or contained.
Step-by-step explanation:
When we consider these options in the context of what can realistically be held for a duration, your breath is a physical action that can be held but typically not for more than a minute or two due to the need for oxygen. A thought, while not a physical object, can be held but often not for a strict duration before the mind wanders. Time cannot be held or controlled, and it is also not a physical object. Lastly, sunshine is light from the sun, and although it is not heavy at all, it cannot be physically held or contained by a person. Based on this analysis, the answer to the riddle is d) Sunshine, as it is impossible to hold sunshine physically, making it the correct answer.