Why is it significant that martha never mentions the war in her letters? what does she represent?

I dont really know what book or article this is from but my assumption is that she represents she may be hiding something or she feels that she cant trust someone.  I may also think that Martha doesnt feel she is safe so she is hiding what she really wants, she could also be in trouble of some sort.  Once again, I have no idea what this is from but im just making an assumption based on the information that you have provided me. 

In a group discussion,which of these is the best example of challenging credibility of a source. the answer choice is a