To find the number that makes the equation \(-\frac{3}{4} + __ = 0\) true, we can isolate the blank by moving \(-\frac{3}{4}\) to the other side of the equation:
\[ __ = 0 + \frac{3}{4} \] \[ __ = \frac{3}{4} \]
Thus, the correct answer is:
D. 3-fourths