The given signal is a periodic signal with a period of 0.1 seconds (as seen from the waveform). The fundamental angular frequency \( \omega_0 \) is related to the period \( T \) by the formula:
\[
\omega_0 = \frac{2\pi}{T}
\]
Substituting \( T = 0.1 \):
\[
\omega_0 = \frac{2\pi}{0.1} = 10\pi
\]
Therefore, the correct answer is option (4).