Concept:Correlation analysis studies the relationship between two variables.Explanation:Correlation analysis seeks to determine whether two variables are related and to quantify the strength and direction of that relationship.Option A refers to regression, not correlation.Option B (establishing relation) is part of correlation.Option C (measuring the extent) is also part of correlation.Therefore, both B and C together describe the aim of correlation analysis.Answer:Option D: Both (b) and (c).