3行2列的矩阵A，修改A的列号为"甲","乙","丙"的命令是： A: rowname(A) <-c("甲","乙","丙") B: rownames(A) <-c("甲","乙","丙") C: colname(A) <-c("甲","乙","丙") D: colnames(A) <-c("甲","乙","丙")

继续上题，为了程序编写简洁，要给数据框x中的6列重新命名为x1,x2,x3,x4,x5,x6,应该使用的命令是（） A: ColNames(x) <- c("x1","x2","x3","x4","x5","x6") B: Names(x) <- c("x1","x2","x3","x4","x5","x6") C: colnames(x) <- c("x1","x2","x3","x4","x5","x6") D: colname(x) <- c("x1","x2","x3","x4","x5","x6")

继续上题，为了程序编写简洁，要给数据框x中的6列重新命名为x1,x2,x3,x4,x5,x6,应该使用的命令是（） A: ColNames(x) &lt;- c(&quot;x1&quot;,&quot;x2&quot;,&quot;x3&quot;,&quot;x4&quot;,&quot;x5&quot;,&quot;x6&quot;) B: Names(x) &lt;- c(&quot;x1&quot;,&quot;x2&quot;,&quot;x3&quot;,&quot;x4&quot;,&quot;x5&quot;,&quot;x6&quot;) C: colnames(x) &lt;- c(&quot;x1&quot;,&quot;x2&quot;,&quot;x3&quot;,&quot;x4&quot;,&quot;x5&quot;,&quot;x6&quot;) D: colname(x) &lt;- c(&quot;x1&quot;,&quot;x2&quot;,&quot;x3&quot;,&quot;x4&quot;,&quot;x5&quot;,&quot;x6&quot;)