In testing, which group is expected to produce a negative result?

• A. Negative control
• B. Positive control
• C. Control group
• D. Blank sample

Answer: (A)

In experiments, a negative control is the group designed so no effect from the test variable is expected. It provides a baseline showing what a “no-signal” result looks like, helping to confirm that any observed effect in the experimental group is truly due to the variable being tested and not contamination or background noise. Because it is specifically arranged to yield a negative result, it’s the best choice here.

A positive control, by contrast, is meant to produce a known positive result to prove the assay can detect the effect. A general control group may serve as a baseline but isn’t defined to guarantee a negative outcome. A blank sample is used to assess background or contamination and is not universally designated as the negative-control group, though it can be negative in some protocols.