请选择ABC3V-T5R2x6Y4j1|6E----It is _________ ruler. ---- It is not __________ eraser.9_0^(P1k+`'@0|
A. /, an9_0^(P1k+`'@0|
B. a; an9_0^(P1k+`'@0|
C. the; the9_0^(P1k+`'@0|