C
...........................
Answer:
I didn't have enough mice in the study.
Explanation:
Validity: In psychological research, the term validity is defined as a particular test's capability of measuring what the test is required to measure. In validity, the term valid refers to strong.
Types: Construct, face, criterion, conclusion, internal, and external validity.
In the question above, they said that the results were not valid because I didn't have enough mice in the study. For any research to work properly or give rise to a valid result then the research should include enough subjects to analyze the effect and therefore by having only two mice doesn't prove the study to be valid.
B. A command economy is solely based on the government controlling all factors in production
