A human resources manager at Beta Technologies, Inc., is trying to determine the variable that best explains the variation of employee salaries using the previously gathered sample of 52 full-time employees in the file P2_1.XLS. Generate scatterplots to help this manager identify whether the employee’s 

(a) Gender, 

(b) Age, 

(c) Number of years of relevant work experience prior to employment at Beta, 

(d) The number of years of employment at Beta, or 

(e) The number of years of post-secondary education has the strongest linear relationship with annual salary.