The diagram is a sketch of part of a tulip flower. The stigma’s real width, represented by the line $PQ$, is $5\,\text{mm}$. The length of line $PQ$ is $15\,\text{mm}$. What is the magnification of the diagram?
- A$\times 0.3$
- B$\times 3$
- C$\times 30$
- D$\times 300$