Which of the following is an effective tool for measuring client satisfaction?​

A) An evaluation survey​
B) ​Single-subject research
C) ​A rapid assessment instrument
D) ​Goal attainment scale

An evaluation survey is an effective tool for measuring client satisfaction as it allows for gathering quantitative and qualitative data on specific aspects of the client's experience with the service. It also provides an opportunity for clients to give feedback on areas where improvements can be made. Other tools listed such as single-subject research, a rapid assessment instrument, and a goal attainment scale may yield important data for different purposes but are not directly related to measuring client satisfaction.