A student used a stage micrometer to calibrate an eyepiece graticule. The stage micrometer had divisions of $0.01\,\text{mm}$ each. When the objective lens was set to $\times 10$, 10 eyepiece graticule units lined up with 10 divisions on the stage micrometer. The same microscope was then fitted with a $\times 40$, rather than a $\times 10$, objective lens to measure the diameter of an alveolus. This diameter was measured as 96 eyepiece graticule units. The eyepiece lens was left unchanged. What is the best estimate for the diameter of the alveolus?
- A$0.960\,\text{mm}$
- B$3.84\,\text{mm}$
- C$240\,\mu\text{m}$
- D$384\,\mu\text{m}$