The correct answer is the option C, which is:
C. G(x)=x-6
The explanation is shown below:
You have that the patern function of the linear function is: F(x)=x. By definition, the patern function is the most basic function in the families of functions. If you have the linear function f(x)=x and you shifted it 6 units down, the function will be: f(x)=x-6, which inficates the it moves 6 units on the –y axis. Therefore, as you can see, the correct answer is the option mentioned above (The option C).