What does it mean when someone asks if an argument is valid?

According to eric shlosser’s introduction to fast food nation what is his book primarily about?

I’m cruel tribute which characters action most advance the development of the plot?

Read the excerpt from the odyssey; 'o cyclops! would you feast on my companions? puny am i, in a caveman's hands? how do you like the beating that we gave you, you d(arn)ed cannibal? eater of guests under your roof! zeus and the gods have paid you! ' according to this excerpt, odysseus (a)is fearful of the cyclops. (b)is prideful and overly confident. (c)has been weakened by the cyclops. (d)has regrets about staying on the island.