A yo$-$yo has a mass m$,$ an outer radius R$,$ and an inner radius $($around which the string is wrapped$)$ R$,.$ The end of the string is held fixed, and the yo$-$yo is allowed to fall while also rotating to unwind the string. We want to know what is the tension $($T$)$ in the string. What is the tension in the string? A$)$ T $=$mg I $(1+$ R$,\text{'}12$ Ro$\text{'})$ B$)$ T $=$mg I $(1+2$ R$,2/$ R$,2)$ C$)$ T $=$mg I $($I $+$ R$,2/2$ R$.\text{'})$ D$)$ T $=$mg I $($I $+2$ R$,2$ I Ro$\text{'})$