An employee of the United States Department of Labor was instructed by his superior to solicit subscriptions to the Department's bulletin on a door-to-door basis in the city in which he worked. While doing so, the employee was arrested for violation of a city ordinance that prohibited commercial solicitation of private residences.

What is the employee's best defense?

A Intergovernmental immunity.

B The First Amendment freedom of expression as it applies to the states through the Fourteenth Amendment.

C The Equal Protection Clause as it applies to the states through the Fourteenth Amendment.

D The city ordinance effectively restricts interstate commerce.