General properties of waves — practice question

The diagram shows a wave. Which row states the wavelength and amplitude of the wave?

• Awavelength $x$, amplitude $y$
• Bwavelength $y$, amplitude $x$
• Cwavelength $x$, amplitude $\frac{y}{2}$
• Dwavelength $\frac{x}{4}$, amplitude $\frac{y}{2}$