For several months, a shoe store owner collects data on the number of children in a group (c) and the total amount of the purchase, in dollars (d). She finds that there is a positive linear association between d and c that is best modeled by the equation d=16.3c+37 .

Which statement is true?

a) The model predicts that for each additional child in a group, the total amount of purchase increases by $16.30.

b) The model predicts that for each additional child in a group, the total amount of purchase increases by $37.00.

c) The model predicts that the average total amount of purchase for a group is $37.00.

d) The model predicts that the average total amount of purchase for a group is $16.30.