Explanation:

- Marked Price of the laptop is Rs65,000.

- Discount offered is 20%. So, the Selling Price = 80% of Marked Price = 0.8 x 65,000 = Rs52,000.

- A Profit of 30% implies that the Selling Price is 130% of the Cost Price (CP).

- Therefore, CP = Selling Price / 1.3.

- CP = 52,000 / 1.3 = Rs40,000.

- Hence, the correct option is Rs40,000.

So, the correct answer is:

- Option 4: Rs40,000

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