Which of the followng best describes how changes in employee activism over the past several years have impacted firms?

a$.$ It has blurred the line between the internal and external environments of the firm

b$.$ It has weakened public opinion of labor unions and strengthened the firm's ability to oppose them

c$.$ It has decreased the amount of attention workers pay to the political actions of top management and shareholders

d$.$ It has led to labor surpluses, making it easier for firms to source top talent