A union declares it will be engaging in a partial strike whereby its employees will alternate between working for a period of time and then walking off the job for an indefinite time. Thus, employees may work for a few days or only a few hours before walking off the job again. The employer claims the union does not have the legal right to engage in a partial strike. Which statement is correct?

a$)$ The employer is correct. The union must either strike or work $-$ it cannot alternate between working and striking.

b$)$ The employer is correct only if the union does not state the specific hours or days workers will be off the job. The law requires the union to provide the employer with at least seven days' notice of when workers will be off the job.

C$)$ The employer is not correct since the NLRA expressly states workers have a right to engage in a partial strike.

d$)$ Whether the employer is correct depends on state law.