18. To assess the accuracy of a laboratory scale, a standard weight that is known to weigh 1 gram is repeatedly weighed a total of n times and the mean of the weighings is computed. Suppose the scale readings are normally distributed with unknown mean and standard deviation =0.01 g. How large should : be so that a 95% confidence interval for has a margin of error of±0.0001? (A) 100(B)196(C)10000(D) 38416