Consider a product with three components in series, with reliabilities of $0\mathrm{.}91,0\mathrm{.}7,$ and $0\mathrm{.}89$ for components $A,B,$ and C $,$ respectively. Furthermore, component B uses a backup that also has a reliability of $0\mathrm{.}7.$ What is the reliability of the system? $($Round answer to five decimal places.$)$

A$.0\mathrm{.}62362$

B$.0\mathrm{.}56693$

C$.0\mathrm{.}70753$

D$.0\mathrm{.}73701$

E$.0\mathrm{.}91000$