Given $f(A,B,C,D)=\sum m(0,1,2,6,8,9,10,11)+\sum d(3,7,14,15)$ is a Boolean function, where m represents min-terms and d represents don’t-cares. The minimal sum of products expression for f is _________
- $f=A\overline{B}+CB$
- $f=\overline{B}+C$
- $f=\overline{D}+A$
- $f=\overline{A}B+\overline{C}D$