The cells of e.m.f. $E_1$ and $E_2$ are connected as shown in figure and $E_1> E_2$. When a potentiometer is connected between point X and Y, the balancing length of potentiometer wire is 150 cm. On connecting the same potentiometer between X and Z, the balancing length is 50 cm. The ratio of emf $E_1$ and $E_2$ is:

3 : 4

The correct answer is Option (2) → 3 : 4