Suppose You Wish to Estimate the Degree to Which a One

Suppose you wish to estimate the degree to which a one dollar increase in the tax on solar power systems affects the percentage of solar power systems sold using state-level data on solar system sales and solar system taxes.You could estimate this effect by regressing the

A) total number of solar systems sold on solar system tax rates.
B) log of total number of solar systems sold on solar system tax rates.
C) log of the total number of solar systems sold on the log of solar system tax rates.
D) log of the total number of solar systems sold on the solar system tax rate.