Answer:
The equation \(y = e^x\) does not have a constant of proportionality (r) in the traditional sense. In this case, \(e\) is the mathematical constant known as Euler's number (approximately 2.71828), and \(x\) is the variable. The expression \(e^x\) represents exponential growth.
So, the correct answer would be:
d) \(r = 1\)