Explanation:

- The listed price of the cellphone is Rs20,000.

- On Sundays, there is a Rs1,000 cash discount. So, the price becomes Rs19,000 (20,000 - 1,000).

- Purchasing with a credit card provides an additional 5% discount.

- 5% of Rs19,000 is Rs950.

- Subtract the Rs950 from Rs19,000 to get the final price of Rs18,050.

- Options given:

- Option 1: Rs18,350

- Option 2: Rs18,900

- Option 3: Rs18,050

- Option 4: Rs18,500

- Option 3: Rs18,050 is the correct answer.