What is the best way to change this sentence from active voice to passive voice?

he defeated the dark knight upon the valley that stretched before the castle fortress.

defeated the dark knight did he upon the valley that stretched before the castle fortress.

before the castle fortress he defeated the dark knight upon the valley that stretched.

the dark knight was defeated upon the valley that stretched before the castle fortress.

upon the valley that stretched before the castle fortress, he defeated the dark knight

the answer should be a)directions.

depends on your school

when i was in high school i took ap biology my senior year and it was the hardest one for me because my teacher finished the material within the first month of school and then went on to doing advanced college level it was horrible. but at a nearby school ap biology was one of the easier aps. also, it depends on what you are interested i like math a lot so ap calculus was easier for me than most but i hate history so ap us government was harder for me than most.