Which of the Following Statements Is True Concerning Phase I

Which of the following statements is true concerning Phase I, II, or III clinical trials?

A) A phase I trial is often very small (N<30) and seeks to determine the safe dose range for a new drug.
B) A phase II trial is often larger than a phase I trial and seeks to determine if a new drug is effective enough to test in a phase III trial and to delineate adverse effects.
C) A Phase III trial compares a new treatment with an established treatment and is usually much larger than either a phase I or a phase II trial.
D) All three of the statements are correct.