Let z₁ and z₂ be two complex numbers such that: $$\left| \frac{z_1 + z_2}{z_1 - z_2} \right| = 1,$$​​

then what is $$Re\left(\frac{z₁}{z₂}\right) + 1$$​ equal to?

Correct option is C

Solution:

​$$\text{Let, } z_1 = 1 \quad z_2 = i\\\left| \frac{1+i}{1-i} \right| = 1\\\text{Re} \left( \left| \frac{z_1}{z_2} \right| \right) + 1 = \text{Re} \left( \left| \frac{1}{i} \right| \right) + 1\\\Rightarrow \text{Re}(-i) + 1= 0 + 1= 1$$​​