Multiply −9 1/2 by 0.04.(1 point)

To multiply \(-9 \frac{1}{2}\) by \(0.04\), we first convert \(-9 \frac{1}{2}\) into an improper fraction.

\[
-9 \frac{1}{2} = -\left(9 \times 2 + 1\right)/2 = -\frac{19}{2}
\]

Now we multiply \(-\frac{19}{2}\) by \(0.04\):

\[
-\frac{19}{2} \times 0.04
\]

Convert \(0.04\) to a fraction:

\[
0.04 = \frac{4}{100} = \frac{1}{25}
\]

Now perform the multiplication:

\[
-\frac{19}{2} \times \frac{1}{25} = -\frac{19 \cdot 1}{2 \cdot 25} = -\frac{19}{50}
\]

Now we need to convert \(-\frac{19}{50}\) to a decimal:

\[
-\frac{19}{50} = -0.38
\]

Thus, the final result is:

\[
\boxed{-0.38}
\]

Therefore, the answer is B: \(-0.38\).