The Yahoos and their slaves, the Houyhnhnms
past participial phrase containing an embedded clause
The answer is A.
An easy way to tell if a sentence is using the passive voice is if you add “by zombies” after the first verb. If the sentence still makes sense after you add “by zombies”, then it’s passive voice. If it doesn’t make sense anymore, then it’s active voice. Also, usually if there is more than one verb in the sentence, it’s passive.
30 pages?!? That’s longer than my lifespan but seriously tho on what?
I think the absolute phrase is "filled with emotion