Answer:
The answer is C
Step-by-step explanation:
All of the other answers have the same domain and range for the function.
The Definition of Porcentage is given by:
Where Vx is discounted value or increased, and Vt is total value. The discount decreases the "p" value.

If you notice any mistake in my english, please let me know, because i am not native.
Answer:
The answer is D. Natural
Step-by-step explanation:
A subset, mathematically, means a category within another set. This can be shown from the picture below.
As you can see, the subset of whole numbers is, in fact, natural numbers.
Since the required number is between 234 and 250, then the first digit of the number is 2 and the second digit can either be 3 or 4.
Let the second and the third digits be x and y respectively, then
2 + x + y = 2y
Consider when the second digit is 3, then
2 + 3 + y = 2y
5 = y
Thus, the number is 235.
Similarly, consider when the second digit is 4, then
2 + 4 + y = 2y
6 = y
Thus, the number is 246.
Since the required number is an even number, therefore, Isabel's number is 246.