b. Which skill(s) will be the most useful to you in life? Give a reason.

I am not sure what skills you are comparing between. However, in this story, the dishonesty that is seen in Joe Keller and his sale of defective parts shows that honesty in business is the most important skill one can have. Ultimate his dishonesty and his greed cause his death and the death of his son.

the question is not specific for anything it in general,

thnx for the rply :)