For lead ${?}_{82}P{b}^{206}($atomic mass $=205\mathrm{.}974440u)$ obtain $($a$)$ the mass defect in atomic mass units, $($b$)$ the binding energy $($in MeV$),$ and $($c$)$ the binding energy per nucleon $($in MeV $).$

$($a$)$ Number $$ Units

$($b$)$ Number $$ Units $$

$($c$)$ Number $$ Units