Can someone please explain why isn’t the 4th Option a right answer too ?

Explanation : Since the side lengths of the rectangle are known. Hence the height of the triangle of ABC is also known. And using that the area of the triangle can be found.

I think its a “must” type question hence we have to choose an answer in which all scenario work , hence if the triangle is inscribed as fig 1 then we can identify the sides and if it isn’t(fig 2) then there is no way to tell the sides.