-    C.P of 3/4th = Rs. (3/4 x 400) = Rs. 300,
  C.P of 1/4th = Rs. 100
  ∴ Total S.P = (90% of Rs. 300 + 110% of Rs. 100) = Rs. 380
 
                    Loss = (20/400 x 100)% = 5%

Let's assume the quantity of sugar purchased by the man to be 1 unit and its cost price to be Rs. 400. Then,

Cost price of 1 unit of sugar = Rs. 400

Total cost price of sugar = Rs. 400 x 1 = Rs. 400

The man sold 3/4 of the sugar at a loss of 10%. So, the selling price of 3/4 unit of sugar can be calculated as:

Selling price of 3/4 unit of sugar = (1 - 10/100) x (3/4) x 400 = Rs. 270

The man sold the remaining 1/4 unit of sugar at a gain of 10%. So, the selling price of 1/4 unit of sugar can be calculated as:

Selling price of 1/4 unit of sugar = (1 + 10/100) x (1/4) x 400 = Rs. 110

The total selling price of sugar = Rs. 270 + Rs. 110 = Rs. 380

Therefore, the man incurred a loss of Rs. 400 - Rs. 380 = Rs. 20.

Now, the profit or loss percentage can be calculated as:

Profit or loss percentage = (Amount of profit or loss / Cost price) x 100%

= (20 / 400) x 100%

= 5%

Therefore, the man gets a loss of 5% on the whole (Option A).

Explanation:

• Cost price is the price at which a product is purchased by the seller.
• Selling price is the price at which a product is sold by the seller.
• Profit or loss is the difference between the selling price and the cost price.
• Profit or loss percentage is the percentage of the profit or loss with respect to the cost price.
• If a product is sold at a higher price than its cost price, the seller gets a profit, and if it is sold at a lower price than its cost price, the seller incurs a loss.
• To calculate the profit or loss percentage, we divide the amount of profit or loss by the cost price and multiply the result by 100%.