If stretching is done during the cool-down, it can the muscle
increase flexibility
decrease flexibility
prepare for activity

increase flexibility.

i think that's right. sorry if it's not.

D. A Vietnamese man who fled Hanoi and joined the Army in the south.

Explanation:

In the poem "Thoughts of Hanoi" by Nguyen Thi Vinh writes about the condition of her home country Vietnam and the past lives that has been destroyed with the war. The poem also acts as a foreseeing of what the future holds for the people.

In the lines given in the question, the speaker seems to be someone who used to be from the north but has now been drafted in the army, fighting for the South. From line 15, the poem talks of the numerous places in the north, which suggests that he had been previously a resident of the north too, considering his knowledge of the place. He seems to reminiscence about the time before the war but all that is gone now. His admission of "I am afraid that one day I'll be with the March-North Army meeting you on your way to the South. I might be the one to shoot you then or you me but please not with hatred" shows that he is fighting not because he hated the North but because he has to. He considers his enemy as a "brother", for they are both from the north irrespective of who he's fighting for now.