$\text { Suppose that an automobile's velocity starting from rest is } v ( t ) = \frac { 240 t } { 5 t + 13 } \text { where } v \text { is }$

Multiple Choice

$\text { Suppose that an automobile's velocity starting from rest is } v ( t ) = \frac { 240 t } { 5 t + 13 } \text { where } v \text { is }$ measured in feet per second. Find the acceleration at 9 seconds. Round your answer to one decimal place.

A) $1.9 \mathrm { ft } / \mathrm { sec } ^ { 2 }$
B) $0.9 \mathrm { ft } / \mathrm { sec } ^ { 2 }$
C) $0.6 \mathrm { ft } / \mathrm { sec } ^ { 2 }$
D) $0.2 \mathrm { ft } / \mathrm { sec } ^ { 2 }$
E) $8.3 \mathrm { ft } / \mathrm { sec } ^ { 2 }$