In which phase of clinical trials is the experimental drug tested on 100 to 500 volunteers with the medical condition or illness that the drug is intended to treat? a. Phase 2 b. Phase 3 c. Phase 1 d. Phase 4

Phase II of clinical trial.

Explanation:

Clinical trials aim to determine the efficiency of a proposed or experimental drug on people before it is finalized and sold into the market.

This is necessary so that the effectiveness and any side effects of the drug could be assessed before hand.

The clinical trial design explains four phases :

Phase I involves trial of the experimental drug on healthy people who come for the trial with own consent. They are paid for the trials.

Phase II involves  comparing the effects of drug with general treatment. In this stage hundreds of effected people receive the drug and another group of hundreds of effected people receive the placebo.

Phase III involves testing of the drug on thousands of patients.

Phase IV involves taking reviews on the effectiveness of the drug. This stage comes after the drug has been released into the market. Any kind of ban on a drug can be imposed at this stage.