please help me answer this.thank you

Every seventh customer 1 point entering a shopping mall is asked to select her or his favorite store 0 Simple Random Sampling 0 Systematic Random Sampling 0 Stratified Random Sampling 0 Cluster Sampling A Municipal Mayor wants to 1 point know whether his constituents are in favor or not of putting satellite markets in other barangays. He wants to select a sample of 500 from his constituents, the youths. adults, and from senior citizens. 0 Simple Random Sampling 0 Systematic Random Sampling 0 Stratified Random Sampling I O Cluster Sampling