Assume you have a vector $x=[5,4,9,3,1]$ in MATLAB. You want to create a new vector $y$ that contains all elements of $x$ but in reverse order. Which of the following commands accomplishes this?

A$.y=$flip$(x)$

B$.y=$reverse$(x)$;

c$.$ end :$-1$:$1$;

D$.y=x(-1)$