You need to include the directive in your program in order to use the time function.

From Google:

"a built-in C++ function that returns the current time(according to your computer system's clock) as seconds elapsed since midnight on January 1, 1970; often used as the seed argument in the srand function; a program that uses the time function must contain the #include <ctime> directive"

I hope this helps you with your question

Answer (b) the meter will display a negative sign;