Based on available information, lead time demand for PC jump drives averages $48$ units $($normally distributed$),$ with a standard deviation of $6$ drives. Management wants an $85\%$ service level. Refer to the standard normal table for $z-$values.

a$)$ What value of $Z$ should be applied?

$1\mathrm{.}04$

$1\mathrm{.}65$

$1\mathrm{.}28$

$2\mathrm{.}06$