Identify the relevant population for the following research foci, and suggest the appropriate sampling design to investigate the issues, explaining why they are appropriate. Wherever necessary, identify the sampling frame as well. 

a) A company wants to investigate the initial reactions of heavy soft-drink users to a new “all natural” soft drink. 

b) A hospital administrator wants to find out if the single parents working in the hospital have a higher rate of absenteeism than parents who are not single. 

c) A researcher would like to assess the extent of pilferage in the materials storage warehouses of manufacturing firms. 

d) The director of human resources wants to investigate the relationship between drug abuse and dysfunctional behavior of blue-collar workers in a particular plant. 

e) A marketer wants to generate some ideas on how women differ from men in acquiring product knowledge about cars.