Ans:
a. c(t)=8(1)^t

b. c(t)=24(1)^t

c. c(t)=8(3)^t

d. c(t)=24(3)^t

the circle graph is not a function.

step-by-step explanation:

the graph of the circle is not a function.

because for a graph to be a function, each value of x must give one value of y

in the circle, the values of x for -2< x< 2 each give 2 values of y.

hence this is not a function.

i would say c is the best answer, hope it's right!

good luck! =)

cutie~