3. Tarzan $(M\mathrm{kg})$ tries to cross a river by swinging from a vine as shown in the figure. The vine is $L$ meter long, and his speed at the bottom of the swing is $V\mathrm{m/s}$. And Tarzan knows that the vine has a breaking strength of $S$ Newton. Find the maximum $V$ that Tarzan would not fall in the river.
(A) $[(S - Mg)M / L]^{1 / 2}$
(B) $(SL / M)^{1 / 2}$
(C) $[2(S - Mg)L / M]^{1 / 2}$
(D) $(2SL / M)^{1 / 2}$
(E) $[(S - Mg)L / M]^{1 / 2}$

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