Consider the matrix $A=\left[\begin{array}{cc}a& 0\\ b& 1\end{array}\right]$ and the vector $u=\left[\begin{array}{c}x\\ y\end{array}\right],$ where $a,b,x,$yinR. We will let the vector $v=Au.$ What sequence of linear transformations can be applied to any vector $u$ such that the output is always equal to $v.$

A shear parallel to the x axis by $k=b,$ and then a stretch by $k=$a along the x axis.

A shear parallel to the y axis by $k=b,$ and then a stretch by $k=$a along the x axis.

A shear parallel to the y axis by $k=a,$ and then a stretch by $k=b$ along the x axis.

A stretch by $k=b$ along the x axis, and then a shear parallel to the y axis by $k=a.$