A device that tests whether the product of two two-bit numbers is equals to "0" is to be designed using combinational logic devices. The circuit can be conveived as a Boolean function F(A,B,C,D) that is equal to "1" whenever the product of the two bits numbers AB and CD is zero. For example if AB =11 (3 decimal) and CD is 10 (two decimal) the product will be a binary number different from "0" (decimal 6) and therefore the output of F(A,B,C,D) will be "0" whereas if AB =11 (3 decimal) and CD is 00 (zero decimal) the product will be "0" (zero decimal) and therefore the output of F(A,B,C,D) will be "1". Which of the given functions provide a minimum expression for the function F(A,B,C,D)?

A'B + CD'

(A+B)' + (C+D)'

ABC + A'D'

None of the above