A hot rolled steel rotating $-$bean test specimen has the following properties $S_{-1}=$

$1050$MPa,$S_{yt}=945$MPaf$=0\mathrm{.}798,a=1337$MPa,$b=-0\mathrm{.}067.$ The fatigue

strength of this specimen corresponding $10500$ cycles to failure is $($select the closest value$)$

$($a$)857$MPa

$($b$)809$MPa

$($c$)903$MPa

$($d$)950$MPa

$($e$)$ None of these