Answer: C. Stratification
Step-by-step explanation: There are diverse samping techniques employed for statistical purposes depending on the tipe and nature of data available or other factors. When a data population is sampled in sects such that the entire data is divided into a equals groups at a fixed intervals based on a certain criteria, it is called stratified sampling. Here, data is divided into strata, with each stratum containing a fixed amount of samples with each partition taking place at regular interval. In the scenario stratification process is employed by sampling at a fixed and regular interval, however, the random nature of the data is not violated.