In enemies from withing, mcarthy makes the claim that a list shows 57 communists working in the US government. does Mcarthy have sufficient evidence to support this claim? No, mcarthy provides only a couple of examples of supposed communists

Yes, mcarthy supports his claim by giving a couple of examples

No, mcarthy says there are communists but doesn't identify any.

21 balloons is the story of professor william sherman's travels.

in 1883, he set off from san francisco for a balloon ride over the pacific and was found a month later floating with 21 balloons in the atlantic ocean. this seemed an astounding feat and everyone wanted to know what had happened.    

professor sherman was loyal, however, and said he would tell his tale first to the western american explorers club in san francisco, of which he was a member. this built up suspense for several chapters before he began to tell of the wonders of his adventures and the amazing island of krakatoa, an island which had just been blown up by a volcano.  

the residents of krakatoa are all millionaires who live under a "gourmet government" of their own devising. we get to see all the incredible adventures that creative people with unlimited resources would create according to the author.

i would believe it would be b., the author wants to draw the reader deeper into the experience