Define the connective * for the Boolean variables X and Y as: X * Y = XY + X' Y'. Let Z = X * Y.Consider the following expressions P, Q and R.P: X = Y⋆Z Q: Y = X⋆Z R: X⋆Y⋆Z=1Which of the following is TRUE?

• A. Only P and Q are valid
• B. Only Q and R are valid
• C. Only P and R are valid
• D. All P, Q, R are valid