If a Rock Is Thrown Upward on the Planet Mars $12 \mathrm {~m} / \mathrm { s }$

If a rock is thrown upward on the planet Mars with a velocity of $12 \mathrm {~m} / \mathrm { s }$ , its height in meters $t$ seconds later is given by
$$y = 12 t - 1.92 t ^ { 2 }$$
Find the average velocity over the time interval $[ 2,3 ]$ .

A) $- 0.6 \mathrm {~m} / \mathrm { s }$
B) $4.4 \mathrm {~m} / \mathrm { s }$
C) $2.4 \mathrm {~m} / \mathrm { s }$
D) $3.4 \mathrm {~m} / \mathrm { s }$
E) $1.4 \mathrm {~m} / \mathrm { s }$