Answer:
3.

Explanation:
All the polynomials in the given option are quadratic.
By the fundamental theorem of algebra, the quadratic polynomial has two roots.
Since the solution set is given as {5}, the quadratic has a repeated root.
In other words the root has a multiplicity of 2.
Hence we have the equation:
, multiplicity 2
This implies that;

We expand to obtain;


The correct choice is the third option.