The correct option is D |x−y|=56
When n is odd:
Then units digit can be occupied by 1,3,5,7,9 and 0 cannot be on thousands place
The number of such numbers is x=8×8×7×5=2240.
When n is even: For any number to be even the last digit should be multiple of 2 i.e., 0,2,4,6,8
Case 1: If unit's place is filled with 0
then the total number is 9×8×7=504.
Case 2: If unit's place is other than 0,
then the total number is 8×8×7×4=1792.
Hence, the total number of even numbers is y=504+1792=2296