Find the minimal form of the logical expression in its DNF form as \begin{equation*} d=x'y'z'+x'yz'+x'yz+xyz' \end{equation*}
My answer:
After grouping $(1,3),(1,4)$ and $(1,4),(2,4)$ cells as doubles and $(1,1)$ cell as single, I obtain the minimal form as \begin{equation*} d=x'y'z'+x'y+yz' \end{equation*} But the answer is $x'z'+x'y+yz'$.
Where am I doing wrong?
The Karnaugh map is a torus, so a rectangle containing $x'y'z'$ can be extended to the other side, becoming $x'z'$.