It is desired to design a combinational circuit that detects whether a 4 -bit two's complement integer, a=[a1,a2,a1+a0, is not equal to 3 or not equal to 4, that is. (a =3) or (a=4). The logic function of such circuit is: F=aa+a2+a1 F=o1+a1+a1 F=a3+a2+a1 F=a3+aj+a3