Explanation:

Let's break down the problem:

- The trader sells both shirts at Rs. 3200 each.

- The total selling price for both shirts is Rs. 6400.

- One shirt is sold at a 25% gain:

- Let the cost price of this shirt be \( x \).

- Selling price = Cost price + 25% of Cost price = 1.25x = Rs. 3200.

- Thus, \( x = 3200 / 1.25 = Rs. 2560 \).

- The total cost price of both shirts is Rs. 6400 (since no overall gain or loss).

- The cost price of the second shirt = \( 6400 - 2560 = Rs. 3840 \).

- Loss on the second shirt = \( Cost price - Selling price = 3840 - 3200 = Rs. 640 \).

- Loss percentage = \( (640 / 3840) * 100 = 16.67% \).

- Option 2 is correct.