Hi there! The answer is A. $750
The salesperson sold the car for 30% (so multiply by 1.3) more than $10,000, which is

Now we can see the difference between the auction and dealership price, which is $3,000
Of this $3,000 the salesperson got a commission of 25%. Therefore we must multiply the preceding outcome by 0.25

Hence, the salesperson's commission is $750