Arrange 叶子 / 落下来 / 一片片 / 从 / 树上 to form a sentence: is 一片片叶子从树上落下来 the only correct option?

Question

This is 排列成句 ("form a sentence") exercise from a Chinese textbook about measure words:

_{量词 训练大全, p.26.}

I infer from the Internet (e.g. here) that a (the (?)) correct answer is:

一片片叶子从树上落下来。

But I wonder if two other possibilities are also acceptable:

从树上一片片叶子落下来。
从树上落下来一片片叶子。

Question: Is 一片片叶子从树上落下来 the only correct option?

Answer 1

This is 排列成句 ("form a sentence") exercise from a Chinese textbook about measure words:

1. 一片片叶子从树上落下来。 = one-after-another (measure word) leaf fall from the tree

2. 叶子一片片(adv)从树上落下来。= The leaves falling one-by-one (adv) from the tree

3. 从树上(落下)一片片叶子(来)。 = one-after-another(measure word) leaf fall from the tree

4. 从树上落下(了)一片片叶子 = one-after-another(measure word) leaf has fallen from the tree

• If you cannot change the character or its order in each phrase, and make 一片片 a measure word (not an adverb) then #1. is the only correct answer.

• 一片片 in #2 叶子一片片(地)从树上落下来 is an adverb, not a measure word

• You have to break up 落下 and 来 in #3

• You have to replace 来 with 了 in #4

Answer 2

The reason why "一片片叶子从树上落下来" is the correct answer is because the complete sentence is "秋天到了，一片片叶子从树上落下来"

I suspected that there is more to the sentence because "一片片叶子从树上落下来" somehow seems "incomplete" to me.

So, 秋天到了, 从树上一片片叶子落下来, & 秋天到了 从树上落下来一片片叶子 both therefore sounds awkward.