To Kill a Mockingbird: List four key moments in the plot involving Tom Robinson.

i would pick a. i think this is more of a personal question though.

“way of writing” should be replaced with “writing style"

“idea” should be replaced with “purpose.”

maybe   “people from a long time ago” should be replaced with “elizabethans.”

the best sentence that shows the best placement for the modifier "on the ice" is the one which contains it in the end of the sentence or in its beggining followed by a comma, that indicates it works as adverbial, dislocated in the sentence.

the girl promptly slid on her rollers on the ice.

on the ice, the girl promptly slid on her rollers.