The table shows the values of x and y, where x is proportional to y. What are the values of M and N ?

Given, x is proportional to y.

$$\begin{aligned}\Rightarrow \frac{6}{M} = \frac{12}{18} \\[1em] \Rightarrow M = \frac{6 \times 18}{12} \\[1em] \Rightarrow M = \frac{108}{12} \\[1em] \Rightarrow M = 9. \\[1.5em] \frac{12}{18} = \frac{N}{6} \\[1em] \Rightarrow N = \frac{12 \times 6}{18} \\[1em] \Rightarrow N = \frac{72}{18} \\[1em] \Rightarrow N = 4.\end{aligned}$$

Hence, Option 3 is the correct option.