Susan conducts an experiment five times and gets a solution concentration of 1.9M, 2.1M, 1.8M, 1.9M, and 2.2M. The known concentration of the solution is 2.0M. Which of the following are true about Susan's results?
A. They are both accurate and precise
B. They are precise but not accurate
C. They are accurate but not precise
D. They are neither accurate nor precise