$\text { A calf that weighs } 80 \text { pounds at birth gains weight at the rate } \frac { d w } { d t } = k ( 1500 - w ) \text {, }$

Multiple Choice

$\text { A calf that weighs } 80 \text { pounds at birth gains weight at the rate } \frac { d w } { d t } = k ( 1500 - w ) \text {, }$ where $w$ is weight in pounds and $t$ is time in years. What is the maximum weight of the animal if one uses the model $w = 1500 - 1420 e ^ { - 0.9 t }$ ?

A) $1500 \mathrm { lb }$
B) $880 \mathrm { lb }$
C) $1420 \mathrm { lb }$
D) $1580 \mathrm { lb }$
E) $2300 \mathrm { lb }$