Answer:
Option (b)
Explanation:
Whenever we want to pass a variable by address and not as value, we have to pass it as reference and reference of a variable can be made by putting '&' in front of the variable.
For example - int number=4; // it is a variable whose value is 4
/*Lets say a function setNum takes it as argument as reference then call will be like below line*/
setNum(&number);