Hello Doeun!

Thanks for asking the question! Let's see if I can help.

To answer your question, No, I do not think "뿌린" and "올린" are different in this context. The reason why I commented as such was because I actually did not see any translation for the "dressed" part at all.

Sentence: "Order a sandwich with Dijon mustard in France or a dressed hot dog in a U.S. ballpark..."
Your answer: "프랑스의 디종 머스타드를 뿌린 샌드위치 또는 미국의 야구경기장에서 먹는 핫도그를 주문해 보세요."

Let's really have a look at this sentence.

First of all, I hope you see that it's not "프랑스의 디종머스타드" in this sentence, it should be "프랑스에서". Correct?

Second, this sentence has a very clear sentence structure in my opinion: "Order A or B." ("A 혹은 B를 주문해 보세요")

Here,

A: 프랑스에서 사먹는 디종 머스타드를 뿌린 샌드위치
B: 미국 야구 경기장에서 먹는 ________ 핫도그.

This blank can be, 소스가 뿌려진, 소스가 발라진, 소스가 올려진, 소스를 넣은, or whatever, it doesn't matter as long as it has something in it that has the meaning of "dressed". Your answer didn't.

Hence, your translation of the word "dressed" should be for the hot dog because the sandwich already has its own description, "with Dijon Mustard".

I sincerely hope this is clear!

- Mason (Instructor)

Now it is clear to me:) Thank you very much for your help