The diagram displays a stage micrometer alongside an eyepiece graticule scale, with a magnification of $\times 400$. At the same magnification, a chloroplast is measured and is found to be 4 eyepiece graticule divisions in length. How long is the chloroplast?
- A$1.0 \times 10^{1}\,\mu\text{m}$
- B$4.0 \times 10^{2}\,\mu\text{m}$
- C$2.5 \times 10^{-1}\,\mu\text{m}$
- D$2.5 \times 10^{-2}\,\mu\text{m}$