单项选择题
下列说法中向量组`\alpha_1,\alpha_2,\cdots,\alpha_n`必定线性相关的是( )
A.`\beta_1,\beta_2,\cdots,\beta_{n-1`可由`\alpha_1,\alpha_2,\cdots,\alpha_n`线性表示;
B.`R(\alpha_1,\alpha_2,\cdots,\alpha_n,\beta_1,\beta_2,\cdots,\beta_{n-1})=R(\beta_1,\beta_2,\cdots,\beta_{n-1});`
C.`R(\alpha_1,\alpha_2,\cdots,\alpha_n)=R(\alpha_1,\alpha_2,\cdots,\alpha_n,\beta);`
D.`\alpha _1 =(\beta _1,\gamma _1)^T,\alpha _2 = (\beta _2,\gamma _2)^T, \cdots ,\alpha _n =(\beta _n,\gamma _n)^T`,其中`\gamma_1,\gamma_2,\cdots,\gamma_n`线性相关。