Critical thinking based on an actual situation. In the practical world, usually the higher the reliability of goods and services, the higher their cost. You won a contract to install an A$/$C system at an airport. The system must consist of two items A and B in series. The contract stipulates a total system reliability of $95\%.$ Item A has a reliability of $98\%$ but is expensive. Item B is cheaper but its reliability is only $80\%.$ Together, A and B will not meet the $95\%$ requirement $(98\%$ x $80\%=$ only $78\mathrm{.}4\%).$ So you decide to add item C$,$ as backup to item B$.$ As a critical thinker, you seek to purchase item C at the lowest price possible, as long as C is certified to have a $\_\_\_\_$ percent.

A$.$

maximum reliability of $86\mathrm{.}9$

B$.$

maximum reliability of $84\mathrm{.}5$

C$.$

minimum reliability of $85\mathrm{.}4$

D$.$

minimum reliability of $86\mathrm{.}9$

E$.$

minimum reliability of $84\mathrm{.}5$