Explanation:

- The marked price of the article is Rs 1800.

- It is sold for Rs 1476.

- The difference between the marked price and the selling price is the discount.

- Discount = Rs 1800 - Rs 1476 = Rs 324.

- The discount percentage is calculated as follows:

$$

\text{Discount Percentage} = \left( \frac{\text{Discount}}{\text{Marked Price}} \right) \times 100

$$

- $$

\text{Discount Percentage} = \left( \frac{324}{1800} \right) \times 100 = 18\%

$$

- Option 4: 18% is the correct answer.