pls fast this is c language

int Marks [20]= { 70,85, 60, 55,90, 100,50); For the above code, answer the following questions in the space provided below: 1. Find the size of Marks array. 2. How many number of elements are present in Marks array? 3. Find the index value for last element in array 4. Find the index value for the element 60 5. Find the value of Marks [2] + Marks[0] in Marks array