Write Python code to achieve the following tasks:
a. Calculate and print the number of minutes in a year.
b. Take the radius of a sphere (a floating-point number) as input and then output the sphere's diameter, circumference, surface area, and volume.
c. Calculate the total amount of a meal purchased at a restaurant. The program should ask the user to enter the charge for the food, then calculate the amounts of an 18 percent tip and 7 percent sales tax. Display each of these amounts and the total.