A $4-$N object$$ object swings on the end of a string as a simple pendulum. At the bottom of the swing, the tension in the string is $9$ N$.$ What is the magnitude of the centripetal acceleration of the object at the bottom of the swing? Give the answer as a function of the acceleration due to gravity, g$.$

Group of answer choices

$2$g

$0$

g$/2$

g

$5$g$/4$

$3$g$/2$