Verified Answer :

\(s= r\theta\\\\ s=3\cdot\dfrac{2\pi }{7}=\dfrac{6\pi}{7}\)

Answer: Option 'C' is correct.

Step-by-step explanation:

Since we have given that

\(\theta=\frac{2\pi}{7} \\\\r=3\ cm\)

An arc is a part of total circumference of circle and length of that arc is the measurement of linear distance.

Since we know the formula for "Length of an arc " , we get

\(L=r\times \theta\\\\L=\frac{2\pi}{7}\times 3\\\\L=\frac{6\pi}{7}\)

Hence, Option 'C' is correct.