How many numbers between 40,000 and 50,000 can be formed with the digits 0, 1, 2, 3, 4, 5, 6 when the repetition of digits is not allowed?  Ops:   A. 480    B. 880    C. 360    D. 720

To solve this problem, we need to consider the constraints of the problem.

1. The number must be between 40,000 and 50,000. This means the first digit must be 4 (1 way to do this).

2. The remaining 4 digits can be any of the remaining 6 digits (0, 1, 2, 3, 5, 6), but they cannot repeat.

3. For the second digit, we have 5 choices (0 cannot be used because it would make the number less than 40,000).

4. For the third digit, we have 5 choices left (we've used two digits already and we can't repeat).

5. For the fourth digit, we have 4 choices left.

6. For the fifth digit, we have 3 choices left.

So, the total number of numbers is 1 (for the first digit) * 5 (for the second digit) * 5 (for the third digit) * 4 (for the fourth digit) * 3 (for the fifth digit) = 300.

So, the answer is not in the options. There seems to be a mistake in the problem or the options.