Answer:
The correct option is: a. Photosphere
Step-by-step explanation:
Sun is the brightest star in the sky of our planet Earth and the principle component of the Solar System. It is a gaseous object that is made up of hot plasma and contributes 99.86% to the total mass of our Solar System.
The Sun does not have a clearly defined surface. The visible surface of the Sun is known as the Photosphere, which is the deepest visible portion of the Sun.