The details that best support the theme that oppression can make alternatives seem impossible are:
A. “This was not what they had aimed at when they had set themselves years ago to work for the overthrow of the human race.”
D. “She would remain faithful, work hard, carry out the orders that were given to her, and accept the leadership of Napoleon.”
According to the given exxcerpt, we can see that Clover is reminiscing the old days before the animals rebelled against their masters.
She believes that the promise of a utopian and equal society for all the animals has not been actualised as there was fights, and ruthless qusts for power among the animals themselves
She however notes that even as things were bad, she preferred it to the whip of the humans.
As a result of this, the details which supports the theme that oppression can make alternatives seem impossible are:
Where she reflected on how things have changed
How she would accept her fate and obey the leadership of Napoleon.
Therefore, the correct answers are options A and D