What type of study is described in the following excerpt? Surveys to evaluate nurse satisfaction, medical errors, depression and anxiety, and demographics were given to 5,432 nurses from hospitals of various sizes and geographic locations; some had nurses working 8-hour shifts and 12-hour shifts. Nurses were asked to complete the survey. Upon completion of the survey, nurses were invited to participate in video conference focus groups and one-on-one interviews with a research assistant by video conferencing. Survey results were reported using descriptive statistics, and themes were identified and reported from the data collected in the focus groups and one-on-one interviews.

A.
Quantitative research

B.
Qualitative research

C.
Quasi-experimental research

D.
Mixed-methods research

E.
Systematic reviews