求指导本题解题过程，谢谢您！设有向量组 (alpha )_(2)=((1,-1,2,4))^7 , (alpha )_(2)=((0.3,1,2))^7 , (alpha )_(3)=((3,0.7,14))^7,-|||-(alpha )_(4)=((1,-2,2,0))^7 , (alpha )_(5)=((21.5,10))^7, 则该向量组极大无关组是 .-|||-A α1:α2:α3;-|||-B α1:α2,α4;-|||-C α1:α2:α3;-|||-D a1:a2,α4,α5

求指导本题解题过程，谢谢您！