In Microsoft Visual Studio (C#):

An Internet service provider offers four subscription packages to its customers, plus a discount for nonprofit organizations:

Package A: 10 hours of access for $12.95 per month. Additional hours are $4.00 per hour.

Package B: 20 hours of access for $14.95 per month. Additional hours are $2.00 per hour.

Package C: 30 hours of access for $20 per month. Additional hours are $1.00 per hour.

Package D: Unlimited access for $35.95 per month.

A nonprofit organizations will get 20% discount on all packages.

The user should select the package the customer has purchased from a set of radio buttons and enter the number of hours used in a textbox. A check box captioned Nonprofit organization should appear on the form. The application should calculate and display the total amount due with a textbox.

Input validation: The number of hours used in a month must contain digits only and cannot exceed 744. You must use Validating event to do the validation.

Test your program with these data:

a. Package B using 25 hours, not non-profit: cost: $24.95

b. Package C using 40 hours, is non-profit: cost;$24