Which statement best describes this demonstration?

A.

Step one contains a compound, which is chemically combined in step two, forming a mixture in step three.
B.

Step one contains a compound, which is physically combined in step two, forming a mixture in step three.
C.

Step one contains a mixture of elements, which are physically combined in step two, forming a new compound in step three.
D.

Step one contains a mixture of elements, which are chemically combined in step two, forming a new compound in step three.

D. Step one contains a mixture of elements, which are chemically combined in step two, forming a new compound in step three.