To find the profit percent of the shopkeeper, we need to first find the selling price of the article and then calculate the profit percentage using the formula:

Profit Percentage = (Profit / Cost Price) * 100

Let's break down the given information step by step:

1. The customer saves Rs. 320 at a rebate of 20% on the market price of the article.
- This means the customer paid 80% of the market price.
- Let the market price be 'M'.
- So, the customer paid 80/100 * M = 0.8M rupees.

2. The cost price of the article for the shopkeeper is Rs. 1000.
- This is the amount the shopkeeper paid to acquire the article.

3. To find the selling price, we need to add the profit to the cost price.
- Let's assume the selling price is 'S'.

4. The profit made by the shopkeeper can be calculated by subtracting the cost price from the selling price.
- Profit = Selling Price - Cost Price
- Profit = S - 1000

5. We know that the customer saved Rs. 320, which means the selling price for the customer is 320 rupees less than the market price.
- S = M - 320

6. Substituting the value of S from step 5 into the equation in step 4, we get:
Profit = (M - 320) - 1000
Profit = M - 1320

7. Now we can calculate the profit percentage using the formula mentioned earlier:
Profit Percentage = (Profit / Cost Price) * 100
Profit Percentage = ((M - 1320) / 1000) * 100
Profit Percentage = (M / 1000) * 100 - 132

8. Since the profit percentage is the same as the rebate percentage (20%), we can equate the two:
(M / 1000) * 100 - 132 = 20

9. Solving this equation, we find:
(M / 1000) * 100 = 20 + 132
(M / 1000) * 100 = 152

10. Simplifying further:
M / 10 = 152
M = 152 * 10
M = 1520

11. Now that we know the market price, we can calculate the profit percentage:
Profit Percentage = (M / 1000) * 100 - 132
Profit Percentage = (1520 / 1000) * 100 - 132
Profit Percentage = 152 - 132
Profit Percentage = 20

Therefore, the profit percentage of the shopkeeper is 20%, which corresponds to option 'B'.