Under What Conditions Must an Employer Allow Non-Employee Union Solicitation

Under what conditions must an employer allow non-employee union solicitation on company property?

A) if there is currently no union representing the company's employees
B) if the employees live in a company town such that it would be difficult to solicit the employees off of company property
C) if the purpose is to solicit employees to change union representation, rather than to solicit non-union workers to join a union
D) if the purpose of the union is to address issues other than wages
E) if the non-employee is a former employee, and the solicitation is related to the dismissal