The suns energy reaches the sun by

Conduction

Convection

Radiation

Fusion

Radiation

Explanation:

Radiation.

It is by Radiation.

Conduction of heat is the process by which heat energy is transferred through a material, the average position of the particles of the material remaining the same. eg cloth, cork, wood etc.

Convection is the process by which heat is transferred in a liquid or gas by the actual movement of the heated fluid from the hotter to the colder parts.

Radiation is the process by which heat is transferred from a hotter to a cooler place with heating of the intervening medium.

Fusion (melting) is the process whereby a substance changes from solid state to a liquid state when heat is applied to it.