1. Using switch statement, write a C program to do the following problems: [0.5 mark] A) If the user enters 1, the program prints the following structure using while loop: 1 22 333 4444 55555 B) If the user enters 2, the program prints the following structure using while loop: 12345 1234 123 12 1 B) If the user enters 2, the program prints the following structure using while loop: 1234 5 1234 123 12 2. Write a function that takes two integer inputs and returns the sum of all even numbers between these inputs, and another function that takes two integer inputs and returns the sum of odd numbers between these inputs .In main function, the program will asks the user to enter two integer numbers and then passes them to these two functions and display the result of each of them. [0.5 mark] A. Write a C program to process a collection of the speeds of vehicles. Your program should count and print the number of vehicles moving at a high speed (90 miles/hour or higher), the number of vehicles moving at a medium speed (50-90 miles/hour), and the number of vehicles moving at a slow speed (less than 50 miles/hour). It should also display the category of each vehicle. Test your program on the following data: Speed of vehicles (in miles): 43 23 54 57 68 67 51 90 33 22 11 88 34 52 75 12 78 32 89 14 65 67 97 53 10 47 34 B. Modify your program to display the average speed of a vehicle (a real number) at the end of the run. [0.75 mark] 4. Write a C program that asks the user to enter 15 integer numbers and then store them in the array. Then, the program will find the second largest clement in array and its index without sorting the array. For example, In this array (-55,-2,1, 2, -3, 0, 5, 9, 13, 1, 4, 3, 2, 1, 0}, the second largest element is 9 [found at index 7]. [0.75 mark]