Find the Term That Should Be Added to the Expression $x^{2}-\frac{5}{2} x$

Find the term that should be added to the expression to form a perfect square trinomial. Write the resulting perfect square trinomial in factored form.
- $x^{2}-\frac{5}{2} x$

A) $\frac{25}{4} ;\left(x-\frac{5}{4}\right) ^{2}$

B) $\frac{25}{16} ;\left(x+\frac{5}{4}\right) ^{2}$

C) $\frac{25}{16} ;\left(x-\frac{5}{4}\right) ^{2}$

D) 0 ; $\left(x-\frac{5}{4}\right) ^{2}$