Answer:
23
Step-by-step explanation:
The user is prompted to enter the starting number and ending number, which in this case are 10 and 15 respectively. The variable x is assigned the value of 3. The variable sum is initialized to 0. The for loop is executed, with the loop variable i taking on the values start, start+x, start+2x, and so on, up to but not including stop. In this case, the loop variable i will take on the values 10, 13, and 16 (since start is 10, and x is 3). The loop will not include 15 because it is the stopping point and not included. The statement sum = sum + i adds each value of i to the sum variable on each iteration of the loop. After the loop has completed, the value of sum (which is 10 + 13 = 23) is printed. So the correct answer is 23.