You perform a travel cost study that looks at the relationship between the cost of visiting a lake (including costs of travel, value of time spent not working & any entry fees), its water quality (measured by the concentration of fecal coliform bacteria) and the actual numbers of visitors.  Circle the categories of values (willingness-to-pay) that this method can potentially uncover for individuals (there may be more than one).

a. Changes in recreational use value related to planned improvements in water quality