Determine a Formula for the Exponential Function $y = 2.8 x$

Multiple Choice

Determine a formula for the exponential function.
-The graph of an exponential function is given. Which of the following is the correct equation of the function?

A) $y = 2.8 x$
B) $y = 0.73 ^ { x }$
C) $y = 3.9 \mathrm { x }$
D) $y = 0.45 ^ { x }$