Step 1: Understand the problem.
We are asked to find the number of products that had a 100% market share in all four cities (Bangalore, Calcutta, Delhi, and Chennai) in 1983 and 1984.
Step 2: Analyze the data for each product.
For Product AB:
- In Bangalore: 30 (1983), 25 (1984)
- In Calcutta: 45 (1983), 40 (1984)
- In Delhi: 60 (1983), 25 (1984)
- In Chennai: 30 (1983), 40 (1984)
Since the quantity sold in each city varies, Product AB does not have a 100% market share in any of the cities.
For Product CD:
- In Bangalore: 30 (1983), 35 (1984)
- In Calcutta: 40 (1983), 25 (1984)
- In Delhi: 25 (1983), 20 (1984)
- In Chennai: 30 (1983), 25 (1984)
Similarly, Product CD does not have a 100% market share in any of the cities.
For Product EF:
- In Bangalore: 55 (1983), 25 (1984)
- In Calcutta: 35 (1983), 20 (1984)
- In Delhi: 45 (1983), 45 (1984)
- In Chennai: 20 (1983), 20 (1984)
Product EF does not have a 100% market share in any of the cities either.
For Product GH:
- In Bangalore: 50 (1983), 30 (1984)
- In Calcutta: 45 (1983), 40 (1984)
- In Delhi: 20 (1983), 20 (1984)
- In Chennai: 60 (1983), 55 (1984)
Product GH does not have a 100% market share in any of the cities.
Step 3: Conclusion.
None of the products had 100% market share in all four cities.
Final Answer:
The correct option is (A): 0.