Concept:
Milk production and distribution follow a systematic chain from farm to consumer.
Step 1: Production (A)
• Milk is produced at dairy farms.
• First stage of supply chain.
Step 2: Milk Supply Union (B)
• Milk is collected from producers.
• Organized through cooperative systems.
Step 3: Milk Processing (D)
• Pasteurization, packaging, quality control.
• Ensures safety and shelf life.
Step 4: Consumer (C)
• Final stage where milk reaches end users.
Final Sequence:
\[
A \rightarrow B \rightarrow D \rightarrow C
\]
\[
\boxed{\text{Option (B)}}
\]