One disadvantage of using a survey to gather data for psychological purposes is the fact that it can be a. an inefficient data collection tool b. only used to gather unobservable information c. difficult to use for research purposes d. potentially unreliable or invalid

The correct answer is D. Potentially invalid or unreliable.

Survey is termed as method of research which is used for collecting data in order to gain information from pre-defined group of respondent.

There are certain characteristics of survey. For example, sample size, determinants, use types of questions which are different, measurement scales which have levels which are fundamental and survey administering.