An Astronomer Classifies Nebulae That Have Distinct Geometry by Dividing

An astronomer classifies nebulae that have distinct geometry by dividing the nebulae into

A) two main types, as either absorption nebulae or reflection nebulae.
B) two main types based on their predominate radiation characteristics as either emission nebulae or absorption nebulae.
C) two main types based on their predominate radiation characteristics as either emission nebulae or reflection nebulae.
D) three main types based on their predominate radiation characteristics as either emission, absorption, or reflection nebulae.