In what ways does Franklin fear the delegates may undermine the Constitution even after they sign it? Explain.

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.

i agree, i think a best suits this answer.