A biased die has six faces numbered as $k=1,2,3,4,5$, and $6$. On rolling the die, the probability of the number k appearing is proportional to $k^{2}$. What is the probability that an even number will appear on rolling the die?
- $\frac{35}{91}$
- $\frac{56}{91}$
- $\frac{12}{21}$
- $\frac{9}{21}$
