A system uses 4 switches A, B, C, and D; a combination of switches determines whether an alarm, X, sounds. If switch A and switch B are in the OFF position, and if switch C and switch D are in the opposite position then a signal to sound an alarm, X, is produced.

Design the logic of the circuit. Draw the circuits using the appropriate logic gates. Write down the corresponding Boolean expression and truth table.

Based on the logic table you created, answer the question: is it possible to design an equivalent logic circuit (that is, a different circuit design that produces the same truth table) that will sound the alarm with the same switch combination? If the answer is YES, draw the equivalent circuit.