Answer: The answer is (A) Absolute value.
Step-by-step explanation: Given that we have a function which is symmetric over the line x = 2.
Obviously, the graph of the line x = 2 will be vertical, parallel to Y-axis.
But, the graphs of a cubic function, exponential function and a rational function will not be always parallel to the Y-axis. So, these three options will not work here.
The only correct choice is the absolute function.
For example, for the given line x = 2, the function which is symmetric to it will be of the form

where 'k' is any real number.
The attached figure is drawn for k=2.
Thus, the correct option is (A). Absolute value.