Step 1: Understanding the Concept:
Identify which English word appears in exactly the same sentences as the code 'vin'.
Step 2: Detailed Explanation:
- 'vin' appears in sentence (3) and (4).
- The common word between (3) 'drivers stopped all trains' and (4) 'all passengers were late' is all.
Step 3: Calculation:
By direct comparison, 'vin' = all.
Step 4: Final Answer:
The word represented by 'vin' is all. Thus, the correct option is (a).