$f(A, B, C, D)$ = $\pi M(0,1,3,4,5,7,9,11,12,13,14,15)$ is a maxterm representation of a Boolean function $f (A, B, C, D)$ where $A$ is the $MSB$ and $D$ is the $LSB$. The equivalent minimized representation of this function is
1. $(A +\bar{C}+D) (\bar{A}+B+D)$
2. $A\bar{C}D + \bar{A}BD$
3. $\bar{A}C\bar{D}+A\bar{B}C\bar{D}+A\bar{B}\bar{C}\bar{D}$
4. $(B+\bar{C}+D) (A+\bar{B}+\bar{C}+D) (\bar{A}+B+C+D)$