What Are the Most Common Limitations of Observations

Multiple Choice

What are the most common limitations of observations?

A) They are expensive, completed too quickly, and are limited to one area.
B) They are expensive, time consuming, and are only completed by professional researchers.
C) They are expensive, time consuming, and are limited to one area.
D) They are time consuming, completed by professionals, and require that the observers inform their subjects of the study.