A 37 year-old right-handed male presents with daily headaches for the past 2 months. They are worse in the morning and awaken him from sleep. In the past week, he has noticed a tendency to drop things. Neurologic examination reveals upper extremity strength of 4/5 on the right and 5/5 on the left. Which of the following is the most appropriate next step in the evaluation of this patient?
A. Lumbar puncture (LP)
B. Electroencephalogram (EEG)
C. Magnetic resonance imaging (MRI)
D. Electromyelogram (EMG)