Explanation:

- Marked Price: The T.V. has a marked price of Rs. 8000.

- Discount: A 10% discount is given, reducing the price by 10% of 8000, which is Rs. 800.

- Selling Price: After the discount, the price becomes Rs. 8000 - Rs. 800 = Rs. 7200.

- Profit: The shopkeeper makes a gain of 20% on the cost price.

- Cost Price Calculation:

- Let the cost price be X.

- Selling Price = Cost Price + Profit

- Rs. 7200 = X + 20% of X

- Rs. 7200 = 1.2X

- X = Rs. 7200 / 1.2

- X = Rs. 6000.

- Correct Option: Option 5 - Rs. 6000

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