During Assessment of a Patient's Knee, the Nurse Tests for the Bulge

During assessment of a patient's knee, the nurse tests for the bulge sign. Which technique is the nurse using?

A) The nurse is tapping lightly over the nerve running next to the patella.
B) The nurse strokes the medial aspect of the knee upward and observes for changes.
C) The nurse feels for a fluid wave while moving the patella up and against the femur.
D) The nurse places a thumb and finger on either side of the patella and assesses for fluid in the spaces next to the patella.