CONCEPT:The step-size is a measure of the precision of the DAC and gives US the minimum change in output voltage.\({\rm{Step\;size}} = \frac{{{\rm{FULL\;scale\;voltage}}}}{{{2^{\rm{N}}} - 1}}\)Calculation:Full scale voltage = 5 Vaccuracy = step size = 10 MV\({\rm{Step\;size}} = \frac{{{\rm{Full\;scale\;voltage}}}}{{{2^{\rm{N}}} - 1}}\)2N - 1 = 5000/10= 5002N = 501The best choice is N = 9.