The scatter plot shows the length of a spring (in inches) when a stretch force (in pounds) is applied. The equation represents the linear model for this data. y = 0.73x + 1

What does the number 0.73 in the equation mean in this context?

a The spring has no stretch when a force of 0.73 pound is applied.

b The spring will stretch 0.73 inch for every pound of force applied.

c The spring stretches a distance of 1 inch when a force of 0.73 pound is applied.

d The spring stretches at a rate of 0.73 pound per inch.

e The spring has a length of 0.73 inch when no force is applied.