What is the system reliability of a product consisting of three components arranged in series: component A with a reliability of $0\mathrm{.}85,$ component B with a reliability of $0\mathrm{.}70($backed up by a secondary component with a reliability of $0\mathrm{.}80),$ and component C with a reliability of $0\mathrm{.}80($also backed up by a secondary component with a reliability of $0\mathrm{.}80)?$

Question $40$ options:

$0\mathrm{.}6768$

$0\mathrm{.}4760$

$0\mathrm{.}7670$

$0\mathrm{.}5440$

$0\mathrm{.}8565$