When he came back, his _________ look on his face, he failed in the interview.
A:disappointed
B:disappointing
C:encouraged
D:encouraging
如图,线段AB的两个端点坐标分别为A(1,4),B(6,2),以原点O为位似中心,将线段AB缩小后得到线段A′B′.若AB=2A′B′,则端点B′的坐标为( )