The set of variables f and g
we have to find the set of variables by which the bivariate data represents.
Data for two variables is known as bivariate data.
Eg: No. of Ice cream sold vs the temperature on that day. The two variables are the Ice Cream Sales and Temperature.
Bivariate analysis is one of the simplest forms of quantitative analysis involves the analysis of two variables for the purpose of determining the empirical relationship between them i.e relation between two variables.
Hence, the set of variables are f and g.
Option D is correct.