Which of These Examples Shows the Most Effective Transition from the First

Multiple Choice

Which of these examples shows the most effective transition from the first sentence to the second?

A) New screening techniques are being developed to combat computer viruses. They are the subject of a new research effort at Big State University.
B) New screening techniques are being developed to combat computer viruses. These techniques are the subject of a new research effort at Big State University.
C) New screening techniques are being developed to combat computer viruses. A new research effort at Big State University is focused on fighting computer viruses.
D) New screening techniques are being developed to combat computer viruses. Nevertheless, they are the subject of a new research effort at Big State University.