During an interview or observation, if the participant's behavior changes when the researcher is present, this is termed:

A) reactivity
B) social desirability
C) selection bias
D) responsiveness

Reactivity

The degree to which the process of measurement itself affects the measurement and the subject's behavior.

Social Desirability

The tendency of respondents to answer questions in a manner that will be viewed favorably by others, which can bias survey and research results.

Selection Bias

A distortion in statistical analysis resulting from the method of collecting samples, where the sample obtained is not representative of the population intended to be analyzed.