-    C.P of 20 dozen = Rs.(48 x 20) = Rs.960
  C.P of 8 dozen = Rs. (48 x8) = Rs. 384.
  C.P of 12 dozen =Rs. (960 – 384) = Rs. 576
  Total S.P = Rs. (110/100 x 384 +120/100 x 576) = Rs.1113.60
      ∴ Profit % = (153.60/960 x 100)% =16%

Explanation:

To calculate Sanket's profit percentage in this transaction, we need to determine the total cost and total revenue from the sale of the notebooks.

Let's consider the cost price (C.P) of 1 notebook is Rs. 4. Then, the cost price of a dozen notebooks will be 12 * 4 = Rs. 48.

The cost price of 20 dozen notebooks is 20 * 48 = Rs. 960.

Now, let's calculate the selling price (S.P) of 8 dozen notebooks sold at 10% profit:

• The profit on 1 notebook is 4 * 10/100 = Rs. 0.40
• The selling price of 1 notebook will be 4 + 0.40 = Rs. 4.40
• The selling price of 1 dozen notebooks will be 12 * 4.40 = Rs. 52.80
• The selling price of 8 dozen notebooks will be 8 * 52.80 = Rs. 422.40

Let's calculate the selling price of 12 dozen notebooks sold at 20% profit:

• The profit on 1 notebook is 4 * 20/100 = Rs. 0.80
• The selling price of 1 notebook will be 4 + 0.80 = Rs. 4.80
• The selling price of 1 dozen notebooks will be 12 * 4.80 = Rs. 57.60
• The selling price of 12 dozen notebooks will be 12 * 57.60 = Rs. 691.20

Finally, let's calculate the total revenue from the sale of 20 dozen notebooks:

• Total revenue = revenue from 8 dozen notebooks + revenue from 12 dozen notebooks = 422.40 + 691.20 = Rs. 1113.60

Now, let's calculate the profit percentage:

• Profit = Total revenue - Cost price = 1113.60 - 960 = 153.60
• Profit Percentage = (Profit / Cost price) * 100 = (153.60 / 960) * 100 = 16%

Hence, the correct answer is C) 16.