4. You collect data from 1990-2017 on severance tax revenue and infrastructure expenditures for the state of West Virginia. You estimate the following regression model, expenditures+ = a + +Botaxreve + Btaxrevt-1 + - A. Cross-sectional data and conventional standard errors B. Panel data and clustered standard errors C. Time series data and Newey-West standard errors 5. You collect data from 2015-2017 on severance tax revenue and infrastructure expenditures for all 50 states. You estimate the regression model expendituresit = a + taxrevit + $i+ T2016 2016 2017 2017 + Eit- A. Cross-sectional data and conventional standard errors B. Panel data and clustered standard errors C. Time series data and robust standard errors