A 55-year-old man is referred to the electrodiagnostic lab to find a neuromuscular cause for increasing shortness of breath. His routine nerve conduction study is normal. Needle EMG of the proximal and distal muscles, as well as the thoracic paraspinal muscles, is also normal. The patient requests you to perform a diaphragmatic EMG even though you are not trained in diaphragmatic EMG. The patient really would like to have the study performed right away as he does not want to come back on another day for the study. The best action is

A. Perform the study since this is convenient for the patient

B. Request a colleague who is experienced in diaphragmatic EMG to perform the study

C. Obtain an ultrasound machine to guide you with needle EMG even though you have not used the ultrasound machine before

D. Perform phrenic motor studies and explain to the patient that this will provide as much information as needle EMG of the diaphragm muscle