This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
Which is true about rheobase? 
Select and explain. 
A. Minimum time required to produce action potential, B. Maximum time required to produce action potential, C. Minimum strength of stimulus to produce action potential, D. Maximum strength of stimulus to produce action potential
C: Minimum strength of stimulus to produce action potential
Answer: C: Minimum strength of stimulus to produce action potential 
Explanation: Ans. C Minimum strength of stimulus to produce action potential* Rheobase: The minimum strength of a stimulus, which is able to produce AP in an excitable tissue (e.g. Nerve, muscle), regardless of the duration it takes.* Utilization time: Minimum time (duration) for which the rheobase has to be applied for excitation of tissue.* Chronaxie: Minimum time (duration) for which a stimulus double the rheobase has to be applied for excitation of tissue.