This problem description is for Questions $4-12)$

PBK is a campus coffee store that uses EOQ to manage its inventory of whole bean coffee, the demand for which is known to be a constant $1,440$ pounds$/$year$.$ PBK$\text{'}$s fixed cost associated with placing and receiving an order from its supplier is $$18/$order$.$ Its purchase cost is $$1/$pound$,$ and its estimated $($unit$)$ annual holding cost is $$3\mathrm{.}60/$pound$/$year $($per pound per year$).$

If the actual $($unit$)$ annual holding cost is really $$6\mathrm{.}40/$pound$/$year and PBK could estimate it accurately $($i$.$e$.,$ PBK knew the actual cost when making decision on order quantity$),$ what is the optimal order quantity$/$size in pounds to minimize Annual Inventory Cost?

Question $9$ options:

$120$

$87$

$90$

$110$

$78$

Question $10($Mandatory$)(5$ points$)$