$(5$ pts$)10.$ For an electron in the Bohr model, for the $n=2$ first excited state what is the ratio of the circumference of the orbit to the de Broglie wavelength of the electron? $($That is$,$ what is $2\frac{r}{}.$

$($a$)1$

$($b$)2$

$($c$)3$

$($d$)4$

$($e$)5$

$($f$)$ none of the above answers