$1\mathrm{.}26$ How many significant figures are in the following

$($a$)5\mathrm{.}71{10}^{13}$

$($b$)4\mathrm{.}4{10}^5$

$($c$)3{10}^{-6}$

$($d$)4\mathrm{.}000{10}^{-11}$

$($e$)5\mathrm{.}5550{10}^{-3}$