Which is the best version of this sentence?
a) never one to settle down, walton has worked driving trucks, as a welder, and a lifeguard--all in the past two years.
b) never one to settle down, walton has worked as a truck driver, a welder, and a lifeguard--all in the past two years.
c) never one to settle down, walton has worked as a truck driver, he's done some welding, and a lifeguard--all in the past two years.
d) never one to settle down, walton has worked as a trucker driver, he's been a welder, and as a lifeguard--all in the past two years.

The best version of the sentence is B) Never one to settle down, Walton has worked as a truck driver, a welder, and a lifeguard--all in the past two years.  

This sentence is the best structured since it applies a parallel structure. Parallel structure or parallelism in writing is the repetition of a pattern within the sentence. In this case, the repetition of the structure is present in the use of the verb phrase has worked, followed by as a truck driver, a welder, and a lifeguard. This structure balances writing and gives equal importance to all the occupations that are mentioned.    

i think that the quotes in paragraph 11 contribute to the development of ideas because it provides a good reasoning of the central idea of the text.

what are you asking? this is gibberish.