Given the radius of the circle = 4 cm.
The arc is intercepted by a central angle of 2.5 radians.
So,
[tex]\begin{gathered} r=4\operatorname{cm} \\ \theta=2.5\text{ rad.} \end{gathered}[/tex]The length of the arc is given by the formula:
[tex]A=\theta\cdot r[/tex]Substitute with the given values;
[tex]A=2.5\cdot4=10\operatorname{cm}[/tex]So, the answer will be option C. 10 cm