Confidence limit includes -

Confidence limit Estimate of mean varies from sample to sample. Therefore, instead of single estimate of mean, a confidence interval generates a lower and upper limit of mean. This interval from lower to upper limit is called confidence limit. Confidence limit is distributed on either side of mean and the deviation from the mean is determined by standard deviation. For example 95% confidence limit (area under 2 standard deviation) means that 95% of the values in the distribution will be included in this limit (95% confidence limit → 2 SD). 95% (2 standard deviation) is the most commonly used confidence limit. None - in option 'c', standard error is there instead of standard deviation. "Standard error of a statistic is the standard deviation of the sampling distribution of the statistics" . — Handbook