Nope. The definition talks about the RATES in each direction, but there's no reason that it must happen at any particular STAGE during the whole thing. Choice 'E' even talks about a reaction that doesn't reach equilibrium until it's almost done. The one you want is 'A'.
The statement that is not true is A: 'A dynamic equilibrium occurs when the reaction is more than 50 percent complete.' because dynamic equilibrium can occur at any point, not just when a reaction is significantly complete.
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