If you are looking for the conjuction word in there it is yet
Answer: A) It is odd that war should ever be viewed as an adventurous expedition.
This excerpt describes the experiences of a group of soldiers in the Vietnam War. The paradox in the passage, however, is the fact that the soldier describes this experience as an adventurous expedition. Besides the fact that the statement is odd, it shows the misconceptions that people have about war, and the difficulty in understanding the reality of it.
I think the correct answer from the choices listed above is option C. The best revision that removes the informal language from the passage would be to change only sentence 2 to "This class has given me the opportunity to build skills such as answering phones professionally and using spreadsheets and databases."