Choose the situation that is an example of heat transfer by radiation. an ice cube melts while you hold it in your hand.
b.
hot soup rises to the top of the bowl while cooler soup sinks to the bottom.
c.
coastal temperatures are cooler than temperatures in inland areas.
d.
the sun's energy is transferred through the vacuum of space to the earth

Option (D) is the correct answer.

Explanation:

When energy is emitted in the form of rays or waves then this type of energy is known as radiation.

For example, the sun's energy is transferred through the vacuum of space to the earth is an example of heat transfer by radiation.  

Whereas an ice cube melts while you hold it in your hand, hot soup rises to the top of the bowl while cooler soup sinks to the bottom, and coastal temperatures are cooler than temperatures in inland areas are not example of heat transfer by radiation.

wavelength variability is the right one

no sign of dia of fuel cell