Respuesta :
D is wrong. The last word is horse and it is stressed. It emphasizes the poetic plea of Richard.
C his plays are not rigidly iambic pentameter. It would sound like a nursery rhyme if that were true.
B is not the answer. What B describes is a Troche foot. This definitely Iambic.
A is the answer. The accents fall on Horse horse king for (to stress for is very unusual. Usually it would be unstressed) horse.