The value of

$y=4+\frac{1}{\left(5+\frac{1}{y}\right)}$

$y-4=\frac{y}{(5 y+1)}$

$5 y^{2}-20 y-4=0$

$\mathrm{y}=\frac{20+\sqrt{480}}{10}$

$\mathrm{y}=\frac{20-\sqrt{480}}{10} \rightarrow$ rejected

$y=2+\sqrt{\frac{480}{100}}$

Correct with Option (A)