In the recursive definition of the concatenation of two strings of symbols from a set $\backslash$Sigma $,$ the basis step is: if w $\backslash$Sigma $*,$ then w $\backslash$lambda $=$ w$,$ where $\backslash$lambda is the empty string. With this in mind, select the correct statement of the recursive step below.

Multiple choice question.

If w $\backslash$Sigma $*$ and x $\backslash$Sigma $,$ then w $($wx$)=($w $$ w$)$x$.$

If w $\backslash$Sigma $*$ and x $\backslash$Sigma and y $\backslash$Sigma $,$ then w $($xy$)=($w $$ x$)$y$.$

If w$1\backslash$Sigma $*$ and w$2\backslash$Sigma $*$ and x $\backslash$Sigma $,$ then w$1($w$2$x$)=$ x$($w$1$ w$2)$

If w$1\backslash$Sigma $*$ and w$2\backslash$Sigma $*$ and x $\backslash$Sigma $,$ then w$1($w$2$x$)=($w$2$ w$1)$x$.$

If w$1\backslash$Sigma $*$ and w$2\backslash$Sigma $*$ and x $\backslash$Sigma $,$ then w$1($w$2$x$)=($w$1$ w$2)$x$.$