In Which of the Following Circumstances Is Picketing Unlawful

Multiple Choice

In which of the following circumstances is picketing unlawful?

A) when picketing obstructs customers from entering the employer's place of business
B) when picketing is carried out against the struck employer's product
C) when picketing is carried out against the neutral employer
D) when the employer carries out a "lockout" against the picketers at work premises