Absolute refractory period

Which of the following is true with regard to the absolute refractory period?
Choose one answer.
a. Potassium channels are open and the membrane is hyperpolarized.
b. It immediately follows the relative refractory period.
c. It allows an action potential to procede in two directions along the length of an axon.
d. It occurs when the sodium channels are open.

Incorrect
Marks for this submission: 0/1.

I thought the answer was D but it was incorrect.

I know that it can't be B or C, but can someone explain how A is possible?

i'm doing this quiz now too on ilearn!! the answer is a.

the rest of our answers are:
1e
2d
3e
4d
5d
6e
7b
8e
9a