1. The table tennis training team has 10 players, and every two players form a pair to practice. The number of different pairing methods is ( ).
(A) 972
(B) 945
(C) 864
(D) 891
1.B.
According to the problem, there are a total of $9 \times 7 \times 5 \times 3 \times 1=945$ ways.