Understanding the Problem:
The problem states that the profit is 25% of the cost price. We are required to determine the corresponding percentage of the sales price.

Cost Price and Profit:
The cost price refers to the amount that a product or service costs to produce or purchase. Profit, on the other hand, is the amount earned after deducting the cost price from the selling price. In this case, the profit is given as 25% of the cost price.

Calculating the Selling Price:
To determine the percentage of the sales price, we need to find the relationship between the profit and the selling price. Since the profit is 25% of the cost price, we can express it mathematically as follows:

Profit = 25% of Cost Price

To calculate the selling price, we need to add the profit to the cost price:

Selling Price = Cost Price + Profit

Determining the Percentage:
To find the percentage of the sales price, we need to express the profit as a percentage of the selling price. We can do this by dividing the profit by the selling price and multiplying by 100:

Profit Percentage = (Profit / Selling Price) * 100

Substituting the value of the profit from the given information, we have:

Profit Percentage = (25% of Cost Price / Selling Price) * 100

Since the profit is 25% of the cost price, we can rewrite the equation as:

Profit Percentage = (0.25 * Cost Price / Selling Price) * 100

Answer:
Therefore, the profit percentage is 25% of the selling price. The correct option is a. 25% of the sales price.