1. A four-digit number, with all digits being distinct, the sum of all digits equals 6, and the number is a multiple of 11, then the number of four-digit numbers that meet this requirement is ( ) .
A. 6
B. 7
C. 8
D. 9
Analysis: Number Theory, Divisibility Characteristics, Sum of Digits.
Four-digit number, all digits are distinct, the sum of all digits equals 6, so the four digits that make up the number are $0, 1, 2, 3$. This number is a multiple of 11, so the sum of the digits in the odd positions equals the sum of the digits in the even positions, which is 3. The four-digit numbers that meet the conditions are 3102, 3201, 1320, 1023, 2310, 2013, a total of 6. Choose A.