The graph illustrates how displacement changes over time for two different waves, X and Y. Wave X has frequency $f$ and amplitude $A$. What are the frequency and the amplitude of wave Y?
- Afrequency $\frac{1}{2}f$, amplitude $\frac{1}{2}A$
- Bfrequency $\frac{1}{2}f$, amplitude $2A$
- Cfrequency $2f$, amplitude $\frac{1}{2}A$
- Dfrequency $2f$, amplitude $2A$