need help on a simple bridge question

[civildong]

anyone can help me how the answer C is obtained? see the following problem. Thanks in advance and good luck to all of us

 

[kevo_55]

For this question, I would recommend asking about the specific question from the problem set published by NCEES rather than enclosing a PDF of it.

Sorry I had to edit the post. I wouldn't want for the NCEES to file a complaint with this site.

Thanks.