[单选题]
The number of molecules in one mo i5 3chr,e9gy2ztdlp dx)e. x8 7e/jkfle of a substew) pk;v h;o7 kch97yya*e(naance
A. depends on the molecular weight of the substance.
B. depends on the atomic weight of the substance.
C. depends on the density of the substance.
D. is the same for all substances.