Fill in the blanks.
(A) When a number is divided by 1, then the quotient is __P__ .
(B) When a number is divided by itself, then the quotient is __Q__ .
| P | Q | |
| A | 1 | Number itself |
| B | Number itself | 1 |
| C | Number itself | Number itself |
| D | 1 | 1 |
the correct answer is D