Step 1: Identify the orbit number.
The third excited state corresponds to
\[
n=4.
\]
Step 2: Use the relation for time period.
For the hydrogen atom,
\[
T_n\propto n^3.
\]
Hence,
\[
\frac{T_4}{T_1}
=
\left(\frac41\right)^3
=
64.
\]
Therefore,
\[
T_4
=
64\times1.5\times10^{-16}
=
96\times10^{-16}
=
9.6\times10^{-15}\text{ s}.
\]
Step 3: Write the answer.
Hence,
\[
\boxed{9.6\times10^{-15}\text{ s}}.
\]
Thus,
\[
\boxed{(B)}
\]
is the correct answer.