The Bass Model for product diffusion is given by

Which of the following statements apply to the ratio Y_t-1/M in the Bass Model?

1. Y_t-1/M is a number between 0 and 1.

2. Y_t-1/M increases with time.

3. Y_t-1/M represents the pressure that imitators who have not yet adopted the product feel, as the total number of adopters increases.

4. Y_t-1/M represents the pressure that innovators feel as more imitators buy the product.

a) Both 2 and 4

b) Only 1

c) 1, 2, and 3

d) Both 1 and 4

e) Only 2 and 3