How many genes are required to determine a polygenic trait?

The impression of change on a statement is found on A. What we need are laws to protect working people, to guarantee them fair pay, safe working conditions, and protection against layoffs. 

It states the purpose and want of change directly to its audience.

Other answers do not make an impression of change in the audience;
B. There is a concentration of women in lower paying, menial, unrewarding jobs and an incredible scarcity in the upper level jobs.

          The statement is an information of women's condition.

C. It is true that part of the problem has been that women have not been aggressive in demanding their rights.

         The statement explains a situation but does not demand.

D. If a young college-educated woman walks into an office for an interview, the first question she will be asked is, "Do you type?" 
       The statement is an assumption of an interview.