Answer
The observation is consistent with the answer in part (c).
Work Step by Step
Since the photons of UV-B radiation are more energetic than those of UV-A radiation, or, in other words, have more energy than those of UV-A radiation, they leave more damage to the objects they strike than the photons of UV-A radiation.
Therefore, UV-B radiation poses more threat (sunburn) to humans than UV-A radiation.
The observation is consistent with the answer in part (c).