QUESTION 4 Suppose you are writing a program that involves calculating taxes owed, and the tax calculation involves a fixed tax rate of 0.12 (or 12%). You decide that, as part of your program, you would declare a constant for the tax rate (10 points) a.) Show the C++ code for declaring the constant (Give just the code that declares theconstant, not a complete program) b.) What would be the motivation for declaring a constant rather than just using 0.12 in an expression within an assignment statement? (One or two sentences will be sufficient)