Identify the correct statements regarding sampling:

A. Random sampling ensures that every member of the population has an equal chance of being included in the sample.
B. Convenience sampling is the most reliable method of sampling, as it is convenient and saves time.
C. Stratified sampling involves dividing the population into mutually exclusive subgroups called strata and then randomly selecting samples from each stratum.
D. Sampling error refers to the discrepancy between the sample statistic and the population parameter.
E. Systematic sampling involves selecting individuals from a population at fixed intervals.