Answer:
The answer is "Option D"
Explanation:
Please find the graph file in the attached file.
Using formula:
[tex]\to v= \rho \lambda \\\\\ \to \lambda= 130 \cm \\\\ \to v= 335 \frac{cm}{s}\\\\ \to \rho= \frac{v}{\lambda} \\\\[/tex]
[tex]=\frac{335}{130} \\\\ = 2.57 \approx 2.50 \ Hz[/tex]