Given the following jar test results, which polymer dose should be used?

Container #

$1$

$2$

$3$

$4$

$5$

$6$

Alum $($mg$/$L$)$

$6$

$6$

$6$

$6$

$6$

$6$

Polymer $($mg$/$L$)$

$0\mathrm{.}25$

$0\mathrm{.}5$

$1\mathrm{.}0$

$2\mathrm{.}0$

$3\mathrm{.}0$

$4\mathrm{.}0$

Turbidity $($NTU$)$

$0\mathrm{.}9$

$0\mathrm{.}7$

$0\mathrm{.}4$

$0\mathrm{.}3$

$0\mathrm{.}7$

$1\mathrm{.}0$