Answer:
c. 2 m/s
Explanation:
The speed of a wave is given by:
[tex]v=f \lambda[/tex]
where
v is the speed of the wave
f is the frequency
[tex]\lambda[/tex] is the wavelength
For the wave in this problem, we have
f = 4 Hz is the frequency
[tex]\lambda = 0.5 m[/tex] is the wavelength
So, the speed of the wave is
[tex]v=(4 Hz)(0.5 m)=2 m/s[/tex]