Task: Class Definition Understanding (ontology: Earth_Environment/SWEET)

Which of the following definitions best describes 'oxidation'?

A. Any process that increases the calcium concentration of a subtance.
B. Any process that decreases the pH value of a subtance.
C. the concept is the accumulation of atoms or molecules on the surface of a material. This process creates a film of the adsorbate (the molecules or atoms being accumulated) on the adsorbent's surface. [Wikipedia]
D. Reaction of a substance with oxygen or incorporation of oxygen into a molecule.

Answer: Reaction of a substance with oxygen or incorporation of oxygen into a molecule.