Reply to the Comments on the XENON100 First Dark Matter Results

The recently submitted preprint on the first results from the XENON100 dark matter experiment (arxiv:1005.0380) was followed by a criticism by J.I. Collar and D.N. McKinsey (arxiv:1005.0838), focused on our extrapolation of the scintillation efficiency L_eff to the lowest nuclear recoil energies, where no data and no theoretical model exist. Here we add clarifications on our analysis and comment on their criticism.