Final answer:
The correct option in the final answer is b. When a muscle is stimulated at a high frequency without any relaxation phase, leading to steady maximum tension, this is known as complete tetanus.
Step-by-step explanation:
When a muscle is stimulated repeatedly at a high rate, such that the relaxation phase between contractions is eliminated, this leads to an increase in muscle tension until it reaches a steady maximum. This phenomenon is referred to as complete tetanus. Unlike incomplete tetanus, where there is still a short relaxation phase between contractions, complete tetanus is characterized by continuous contraction due to a very high frequency of stimulation that prevents any relaxation.
The process begins with what is termed wave summation, where the successive signals from the motor neurons pile up on one another, increasing the muscle tension. With further increase in the rate of action potentials, the muscle enters a state of incomplete tetanus with higher tension than a single twitch but with brief relaxation phases. If the stimulation rate continues to rise to an even higher frequency where the relaxation phase disappears entirely, the muscle tension remains consistently maximized, resulting in a state of complete tetanus.
In considering all of the options provided in the question, we can conclude that the correct option is (b) complete tetanus.