Sonji bought a combination lock that opens with a four-digit number created using the digits 0 through 9. The same digit cannot be used more than once in the combination.If Sonji wants the last digit to be a 7 and the order of the digits matters, how many ways can the remaining digits be chosen?

The last digit is fixed as 7, so the first three positions must use three different digits from the other 9 digits. Since order matters, there are 9 choices for the first position, 8 for the second, and 7 for the third: 9 × 8 × 7 = 504. The correct choice is 504.

AI-written and checked against the verified answer.