A periodically repeating signal is shown on the screen of a cathode-ray oscilloscope. The screen is divided into $1\,\\text{cm}$ squares, and the time base is adjusted to $2.00\,\\text{ms cm}^{-1}$. What is the frequency of this periodic signal?
- A50\,\\text{Hz}
- B100\,\\text{Hz}
- C125\,\\text{Hz}
- D200\,\\text{Hz}