Explanation:

- A shopkeeper sold two articles at Rs 9831 each.

- For the first article, he gained 13%, meaning the selling price is 113% of the cost price.

- Let the cost price of the first article be Rs $x$.

- Then, $x\times 1.13=9831$.

- Solving for $x$, we get $x=8700$.

- For the second article, he lost 13%, meaning the selling price is 87% of the cost price.

- Let the cost price of the second article be Rs $y$.

- Then, $y\times 0.87=9831$.

- Solving for $y$, we get $y=11300$.

- Total cost price = Rs 8700 + Rs 11300 = Rs 20000.

- Total selling price = Rs 9831 + Rs 9831 = Rs 19662.

- Overall loss = Rs 20000 - Rs 19662 = Rs 338.

- Overall loss percentage = $(338/20000)\times 100=1.69\mathrm{\%}$.

Correct Answer: Option 4: 1.69% loss