Answer
(a)
Work Step by Step
$y=C(1-e^{-ax})$
or $y=C-Ce^{a(-x)}$
which can be broken down into three transformations in $ y=e^x$
1) x→-ax (Reflection in the y-axis and scale change of x-axis)
Now our equation is $ y=e^{-ax}$
2)y→-y/C (Reflection in the x-axis and scale change of y-axis)
Now our equation is $ y=-Ce^{-ax}$
3)y→y-C (Vertical shift of C units)
Thus the final graph will match closely with the option (a). Also, note that the graph is asymptotic to the equation y=C
