The distance between Earth and Mars is 225 million km. When converted using the conversion factor 1 AU = 1.5 × 108 km, the distance between the planets is . The astronomical unit (AU) is a light-year.

before we can answer, we have to see the choices that are printed there with the question.   that's the only way we can point you to the correct one.

if you already have the answer to (a), then just work out how many periods there are in 1 minute, and that's the answer to (c).

in this image, you can see solar radiation going through ocean water.

no image, but probably absorption