a$.$ Why do we need environmental valuation?$$

b$.$ Stated preference and revealed preference approaches are the two main sets of methods available for environmental valuation. What are the SP methods? What are the RP methods? What are the main differences between stated preference $($SP$)$ methods and revealed preference $($RP$)$ methods?$$

c$.$ What is willingness$-$to$-$pay $($WTP$)?$ What is willingness$-$to$-$accept $($WTA$)?$ How the two differ?$$

d$.$ What are the pros and cons of the Contingent Valuation $($CV$)$ method?$$