Answer the following question given this paragraph: 

Because the Sun is not solid, it does not have a defined outer boundary. It does, however, have a definite internal structure with identifiable layers ( Figure below ). Since the layers are not solid, the boundaries are fuzzy and indistinct. From inward to outward, the layers are: the core, the radiative zone, and the convection zone.


Q: What is the innermost layer of the sun called?

 Choices:

- Convection Zone

- Chromosphere

- Photosphere

- the core

A:
the core
