Concept:
Karnaugh Map (K-Map) is a graphical method used to simplify Boolean expressions by grouping adjacent cells.
Step 1: Plot outputs on K-Map.
First, the values from the truth table (1s for SOP or 0s for POS) are placed into the K-map grid.
\[
\text{This corresponds to step B.}
\]
Step 2: Draw groups (loops).
Adjacent cells containing 1s (or 0s) are grouped in powers of 2 (1, 2, 4, 8...).
This helps reduce variables.
\[
\text{This corresponds to step D.}
\]
Step 3: Identify prime implicants.
From the formed groups:
• Prime implicants are the largest possible groups.
• Essential prime implicants are those covering unique cells.
\[
\text{This corresponds to step C.}
\]
Step 4: Write minimized expression.
Finally, the simplified Boolean expression is written using the identified implicants.
\[
\text{This corresponds to step A.}
\]
Step 5: Final correct sequence.
\[
B \rightarrow D \rightarrow C \rightarrow A
\]
\[
\boxed{(4)}
\]