MCQ
If $\mathrm{S}=\left\{\mathrm{z} \in \mathbb{C}: \frac{\mathrm{z}-i}{\mathrm{z}+2 i} \in \mathbb{R}\right\}$, then :
- A$S$ contains exactly two elements
- B$S$ contains only one element
- C$\mathrm{S}$ is a circle in the complex plane
- ✓$\mathrm{S}$ is a straight line in the complex plane
