2x² + 5x - k = 0space, 2, x, start superscript, 2, end superscript, plus, 5, x, minus, k, equals, 0
In the equation above, kkk is a constant. For what value of kkk does the equation have exactly one distinct real solution?
a) 5/4
b) 25/4
c) 1
d) 5