Hello, I need help doing these exercises in C. I would appreciate it if you could help me.

NOTE: Use selection control structures.

1.Ask the user for the initial of the day of the week and show the name of the full day.The initial letter may be uppercase or lowercase.Use the x for Wednesday.

2.Writ e a program to determine the total amount to pay for a phone call of N minutes

(introduced by the user), taking into account the following:

Calls of 5 minutes or less have a cost of 10 BsF.

Each additional minute from the first 5 costs 2 BsF.

3.The owner of a stationery wants a program that tells him the selling price of a given item.The price is calculated from

according to the following formula: PVP = cost_price + profit.Where the gain will be:

15% if the cost price is less than C$300.

50 crdobas if the cost price is between C$300 and C$600.

25% if the cost price exceeds C$ 600