The diagram displays a trace of a wave on a cathode-ray oscilloscope. The vertical and horizontal gridlines are spaced by $1.0\,\text{cm}$. The voltage scaling is $4\,\text{V cm}^{-1}$ and the time scaling is $5\,\text{ms cm}^{-1}$. Calculate the amplitude and period of the wave.
- Aamplitude $1.5\,\text{V}$, period $4\,\text{ms}$
- Bamplitude $5.0\,\text{V}$, period $10\,\text{ms}$
- Camplitude $6.0\,\text{V}$, period $20\,\text{ms}$
- Damplitude $12.0\,\text{V}$, period $20\,\text{ms}$