a) Write the truth table for the half adder and obtain simplified boolean functions of the outputs. b) Design and draw half adder by using a. AND, OR, inverter gates b. XOR and AND gates c) Write the truth table for the full adder and obtain simplified boolean functions of the outputs of full adder. d) Design and draw full adder by using a. AND and OR gates b. Two half adders and OR gate e) Design and draw four-bit parallel adder by using full adders.