Critique the Following Statement Made by a Student Looking at a TEM

Multiple Choice

Critique the following statement made by a student looking at a TEM image of dolomite. "The TEM image shows regular patterns of small dots, large dots, and tiny dots. The formula for dolomite is CaMg[CO3]2. I think the large dots must be the carbonate groups."

A) The student is correct.
B) The student is probably correct because four atoms will make a larger mark than one atom.
C) The student is probably incorrect because the single metal atoms have a denser arrangement of electrons than the carbonate group.
D) The student is incorrect because the image must not be dolomite. Since there are four types of atoms, the TEM for dolomite should have four sizes of dots.