Throughout the 1920s, Otto Meyerhof, A. V. Hill, and colleagues investigated how cells use energy to power muscle contraction. They determined that during muscle contraction, glycogen is broken down into lactic acid, a product of fermentation. Originally Meyerhof thought that the conversion of glycogen into lactic acid directly powered muscle contraction. This idea was overturned by experiments performed by Einar Lundsgaard. What evidence did Lundsgaard provide to suggest that glycogen breakdown and lactic acid production did not directly power muscle contraction? Choose one: O A. Creatine phosphate infusions into muscle cells inhibited muscle cell contraction. B. Muscle contraction could continue for some time after inhibition of fermentation. C. A pulse of electricity caused muscle contraction in isolated frog muscle tissue. OD. Inhibition of fermentation immediately halted muscle contraction.