下列各组向量中, 向量a , b, c 共面的一组是  (   )

A．a =" (" 4, 2, 1 ), b =" (–1," 2 , 2 ), c =" (" –1, 1 ; 5 ).

B． a =" (" 1, 2, –3 ), b =" (–2," –4 , 6 ) , c =" (" 1, 0 ,5 ).

C．a =" (" 0, 0, 1 ), b =" (–1," 0 , 0 ), c =" (" 0, –1 ; 0 ).

D．a =" (" –2, 3, 1 ), b =" (3," –2 , –2 ), c =" (" –1, 0 ; 2 ).

血IgM正常或增高，IgG、IgA、IgE缺乏见于（）

A.白细胞黏附分子缺陷症

B.中性粒细胞减少症

C.X连锁高IgM血症

D.X连锁无丙种球蛋白血症

E.选择性IgA缺乏症