a number which is used to inform how measurements for a group are spread out from the mean value is called standard deviation.
if most of the numbers are close to the mean value, the standard deviation will be low and if the numbers are more spread out standard deviation will be high.
precision means how close is the value from the previously measured value of any measurement.precision does not refer to the true value.
the measured value which is close to the exact value is called accuracy
from the above definitions, it is evident that standard deviation is the deviation of a group of measurements from their mean value and also the precision tells how close a particular measurement is from its mean measurement value.
since mean cannot be determined for any given single measurement so precision cannot be determined for a single measurement.therefore,option (a) is incorrect.
since standard deviation tells the deviation from mean value but the accuracy tells how close to the exact value of any measurement.hence, option (b) is also incorrect.
hence,standard deviation is an indication of the precision of repeated measurement.so option (c) is correct.