For the circuit below, answer the following questions: (1) When A=0,B=0,C=0,D=0,F2= ? (2) When A=0,B=0,C=0,D=1,F2= ? (3) When A=1,B=1,C=1,D=0,F2= ? (4) When A=1,B=1,C=1,D=1,F2=