identify the solid of revolution generated by revolving the region around the fixed line $l$.

Brief Explanations:

The orange region is a rectangle with one side lying on line $l$. When a rectangle is revolved around one of its sides (the fixed line $l$), every point in the rectangle sweeps out a circular path perpendicular to $l$, forming a cylinder. The left option has an added pointed shape which does not match, while the right option correctly shows a cylinder formed by revolving the rectangle around $l$.

Answer:

The right solid (the orange cylinder with the pointed end on the right, aligned with line $l$)