An Argon laser $($ $=5\mathrm{.}0102$nm$)$ shines down a silica glass fiber$-$optic cable with index of refraction $1\mathrm{.}46.$ What length of cable, d$,$ is required, if the light is to pass through it in $3\mathrm{.}0$ s$?$ Select One of the Following: $($a$)290$m $($b$)420$m $($c$)620$m $($d$)1000$m $($e$)$ Toby