Suppose our output function is the mean of normal distribution, and ${}_0=2,{}_1=-4,{}_2=-3,{}_3=5.$ Suppose further, that for a particular input $h_1=3,h_2=7,h_3=8.$ Then, the mean of the output normal distribution is

$($a$)9$

$($b$)8$

$($c$)3$

$($d$)7$