Question

1. Which street food do you like most among (the) four street food(s)?
- I like fruit sticks the most because they are delicious and nutritious.

(Do we have to use the definite article? Do we have to use 'food' or 'foods' here?)

2. We have talked about street food in the four cities. Would you like to name the cities?
- Yes. They are New York, Ottawa, Brussels, and Beijing.

3. How much is a pretzel?
4. What is the price of a beaver tail?
5. How much does a Brussels waffle cost?
6. How much do I owe you for a fruit stick?
- It's two dollars.
(Are the questions and answers proper?)

Answer 1

1. If you leave "the" out, the implication is that there are only four types, no matter where you go. If you include "the," your reference seems to be the four types right near you (but maybe there are others in other places). This is simply how I take it. Other tutors may have different ideas.

2, 3, 4, and 6 are fine, yes.

5 makes me wonder if there is such a thing as a "Brussels waffle" or if you mean a waffle in Brussels. ???