f(A, B, C, D) = (A + B + C̅ + D̅).(A̅ + C + D̅).(A̅ + B + C̅ + D̅).(B̅ + C).(B̅ + C̅).(A + B̅).(B̅ + D̅)
The minimized function for the above expression is:1
f(A, B, C, D) = (A̅ + D̅) (C̅ + D̅)
2
f(A, B, C, D) = B̅.(A̅ + D̅) (C̅ + D̅)
3
f(A, B, C, D) = (B̅ A̅ + D̅) (C̅ + D̅)
4
f(A, B, C, D) = (B̅.A̅.D̅) (C̅ + D̅)