Which of the following constants can be added to x2 - 3x to form a perfect square trinomial?
A1\(\frac{1}{2}\)
B2\(\frac{1}{4}\)
C4\(\frac{1}{2}\)
A1\(\frac{1}{2}\)
B2\(\frac{1}{4}\)
C4\(\frac{1}{2}\)