How might information about this function (such as the shape of the isoquants) help the campaign manager plan strategy? A. If the isocost lines for television advertisements and letters to potential voters are convex, then the campaign manager should use a combination of the two inputs. B. If television advertisements and letters to potential voters are perfect complementscomplements, then the campaign manager should use them in fixed proportionsthem in fixed proportions. C. If television advertisements and letters to potential voters are perfect substitutessubstitutes, then the campaign manager should use them in fixed proportionsthem in fixed proportions. D. If the marginal rate of technical substitution of television advertisements for letters to potential voters is constantconstant, then the campaign manager should use a combination of the two inputsa combination of the two inputs. E. If the isoquant curves for television advertisements and letters to potential voters are convex, then the campaign manager should use only the cheaper input per voteonly the cheaper input per vote.