Answer:
[tex]\text{B. }0.17\:\mathrm{Hz}[/tex]
Explanation:
The frequency of a wave is given by [tex]f=\frac{1}{t}[/tex], where [tex]t[/tex] is the period of the wave.
Substituting [tex]t=6[/tex], we get:
[tex]f=\frac{1}{6}\approx \boxed{\text{B. }0.17\:\mathrm{Hz}}[/tex]