During refractory period :

Options

A. Nerve transmits impulse very slowly
B. Nerve can not transmit impulse
C. Nerve transmits impulses very rapidly
D. None of the above

Answer

**Step-by-Step Solution:**

1. **Understanding the Refractory Period:**
- The refractory period is a phase following an action potential during which a neuron is unable to fire another action potential. This period is crucial for the proper functioning of nerve impulses.

2. **Analyzing the Options:**
- **Option 1:** "Nerve transmit impulse very slowly."
- This is incorrect because during the refractory period, the nerve is not transmitting impulses at all, not just slowly.

- **Option 2:** "Nerves cannot transmit impulses."
- This is correct. During the refractory period, the neuron is in a state where it cannot generate another action potential, meaning it cannot transmit impulses.

- **Option 3:** "Nerves transmit impulses very rapidly."
- This is also incorrect. Rapid transmission of impulses occurs during the action potential phase, not during the refractory period.

- **Option 4:** "None of the above."
- This option is incorrect because we have already identified that option 2 is correct.

3. **Conclusion:**
- The correct answer is that during the refractory period, nerves cannot transmit impulses.