Which of the Following Is an Example of a Study

Which of the following is an example of a study focused on performance-related outcomes?

A) A study of the effect of early ambulation on prevention of bed sores.
B) A study on patient compliance with weight-bearing status following hip replacement.
C) A study on the effectiveness of antiemetics given prophylactically with chemotherapy treatment
D) A study on the length of stay after a caesarian section in relation to frequency of nursing assessments