He helps me in times of crisis.

Dear all,

Could you please tell me whether we can say the following things. If yes, please tell me the difference in their meaning?

1) He helps me in times of crisis.

2) He helps me in time of crisis.

3) He helps me in the times of crisis.

4) He helps me in the time of crisis.

5) He helps me at the time of crisis.

6) He helps me at the times of crisis.

7) He helps me during the time of crisis.