- A'B' + A'C' + B'C + ABD'
- A'C' + B'C + ABD'
- A'B' + C'D' + ACD'
- A'B' + A'C' + AC
- A'B' A'C' + B'C + BC'D'

1 is WRONG. This response is a correct representation, but is not as consise as one of the remaining answers. You do not need grouping A'B'; it is redundant.