This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Which of the following best defines the "Saccade": 
Select and explain. 
A. Voluntary slow eye movements, B. Involuntary slow eye movement, C. Abrupt, involuntary slow eye movements, D. Abrupt, involuntary rapid eye movements
D: Abrupt, involuntary rapid eye movements
Answer: D: Abrupt, involuntary rapid eye movements 
Explanation: Ans. Abrupt, involuntary rapid eye movements