A new drug has been approved for use, and the drug manufacturer has made it available for sale. During the first 6 months, the FDA receives reports of severe adverse effects that were not discovered...

A new drug has been approved for use, and the drug manufacturer has made it available for sale. During the first 6 months, the FDA receives reports of severe adverse effects that were not discovered during the testing and considers withdrawing the drug. This illustrates which phase of investigational drug studies? a Phase I b Phase II c Phase III d Phase IV