A void function named calc Ending Inventory is passed four int variables named begin Inventory, sales, purchases, and ending Inventory. The function's task is to calculate the ending inventory, using the beginning inventory, sales, and purchase amounts passed to the function. The function should store the result in the ending Inventory variable. Which of the following function headers is correct?
a. void calc Ending Inventory(int b, int s, int p, int &e)
b. void calc Ending Inventory(int b, int s, int p, int e)
c. void calc Ending Inventory(int &b, int &s, int &p, int e)
d. void calc Ending Inventory(&int b,&int s, &int p, &int e)