During a sunny afternoon, the sun suddenly seems much less bright than usual. The daylight seems much less intense, as if there is a dense cloud cover, but there are no clouds in the sky. After about a half hour, everything seems normal again. Which claim about the temporary decrease in light can be supported by the evidence?
O The moon was passing between the sun and Earth
O An airplane was flying overhead and blocked the light from the sun
O There are variations in the amount of light produced by the sun
O A sudden change in temperature increased the density of the atmosphere