we know that
[tex](x-a)^{2} =x^{2} -2ax+a^{2}[/tex]
we have
[tex]x^{2}- 5x + (\ )[/tex]
in this problem
[tex]-2ax=-5x\\2a=5\\a=(5/2)[/tex]
Substitute
[tex](x-\frac{5}{2})^{2} =x^{2} -2*\frac{5}{2}x+(\frac{5}{2})^{2}\\ \\= x^{2} -5x+(\frac{25}{4})[/tex]
therefore
the answer is the option C
[tex]\frac{25}{4}[/tex]
