What Is the Significance of the Second Function Argument in the Following

What is the significance of the second function argument in the following line
Window.setInterval( "run() ", 100 ) ;

A) The value sets how many times to call the function specified in the first argument.
B) The value sets how long the function is run for.
C) The value sets how often to run the function.
D) The value sets the time to wait before calling the function once.