Which statement(s) is(are) true?

a.
The map is the only representation of the Earth that preserves distance, area, shape, and angles.
b.
The Sun is the primary source of longwave radiation reaching Earth, while Earth releases primarily shortwave radiation.
c.
Geographers observe patterns and processes over space and time.
d.
The shape of the Earth is best described as a sphere.
e.
All of the above.
f.
None of the above.