Which of the following statements does NOT describe a river delta? sediment that builds up where a river meets a larger body of water
earth scooped out that can form a lake or deep valley
where a flowing river empties its load at the mouth of a river
some are muddy and unstable; others are so big crops can grow on them

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.