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

Which of the following definitions best describes 'chemical'?

A. A chemical the concept is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. The term is also used to refer to a pure chemical substance composed of atoms with the same number of protons. [Wikipedia]
B. An the concept is an atom or molecule where the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. [Wikipedia]
C. A chemical the concept is a pure chemical substance consisting of two or more different chemical elements[1][2][3] that can be separated into simpler substances by chemical reactions[4] and that have a unique and defined chemical structure. Chemical compounds consist of a fixed ratio of atoms[3] that are hold together in a defined spatial arrangement by chemical bonds. [Wikipedia]
D. the concept substance, in chemistry, are material objects that can undergo various transformations related to artificial or natural phenomena [Wikipedia]

Answer: the concept substance, in chemistry, are material objects that can undergo various transformations related to artificial or natural phenomena [Wikipedia]