Answer:
A
Step-by-step explanation:
We are constantly thinking, therefore producing thoughts. Thoughts can be negative or positive, though in this case, they are describing the negativity of thoughts.
A dream is a story of our thoughts, one bad one, and our sleep is ruined, this is a very negative effect. Personally, "pollutes" makes the picture darker, and more severe.
Our day is filled with ups and down, if we focus on the 'downs' then our day can be ruined and our mood will be soured. This is definitely a negative effect.
We can choose to be happy or to choose the negative: weep.
Likewise, we can choose to embrace and make a friend of our troubles or we can ignore all the bad and all our woes and focus on the good.
We can choose to be happy or sad and this poem explains that.
It is not b. because it only briefly mentions sleep.
It is not c. because while motivation is a subtopic, it is never mentioned in this poem.
And it is not d. because, while it does explain that we can choose it more specifically highlight the negative.
So your answer is A.