To solve \(-\frac{8}{15} + \frac{4}{15}\), we can combine the fractions since they have a common denominator:
\[ -\frac{8}{15} + \frac{4}{15} = \frac{-8 + 4}{15} = \frac{-4}{15} \]
Thus, the answer is \(-\frac{4}{15}\).
The correct choice is B. -4/15.