A void function named getInventory is passed four int variables named beginInv, sales, purchases, and endInv. 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 endInv variable. Which of the following function headers is correct? 

a. void getInventory(int b, int s, int p, int &e) 

b. void getInventory(int b, int s, int p, int e) 

c. void getInventory(int &b, int &s, int &p, int e) 

d. void getInventory(&int b, &int s, &int p, &int e)