In General,which of the Following Is Least Likely to Unconstitutionally

In general,which of the following is least likely to unconstitutionally burden interstate commerce?

A) A state law requiring that all state vehicles burn gasoline produced and refined within the state.
B) A state law imposing tougher purity standards on food imported from out of state than from food produced in-state.
C) A state law requiring in-state liquor distillers to post the prices at which they will sell in-state,and not to exceed those prices when they sell in other states.
D) A state tax on gasoline that makes it more expensive for trucking companies to route their trucks through the state.