Most serious students are happy students, and most serious students go to graduate school. Furthermore, all students who go to graduate school are overworked.

Question: Which one of the following can be properly inferred from the statements above?
Options:
A. Most overworked students are happy students., B. Some happy students are overworked., C. All overworked students are serious students., D. Some unhappy students go to graduate school., E. All serious students are overworked.
Answer: "B"