The three principles (three Rs) of rapid prototyping are .
a. develop a rough model, rapidly, and for the right price
b. develop a complete model, rapidly, and for the right problem
c. develop a rough model, rapidly, and for the right problem
d. develop a right model, roughly, and for the right price

a. develop a rough model, rapidly, and for the right price

Explanation:

As we are doing a prototype and not a final product a rough model woul fullfil the demand.

As quickly (rapidly) we can do it, more time has the other person to decide upon continue or not

The right price will be to charge for the materials and labor spend not charging a profit margin like it was a final product as the customer will avoid to request in the future if our rate is much higher than others from the start.

d) social security number

let me know if i am correct or not, so i can edit the answer.