The sentence is in the second person singular (you). Therefore, the correct pronoun is tú.
These sentences can be complete in the following way:
1) Nadie.- this would mean that you do not know anyone.
2) Ningún- it makes reference to the book. you do not have a book
3) nunca. This means that you do not do that activity. you never do it
4) ni. not having one thing nor the other.
5) nada. this means that the table is empty- nothing on it.
B- poorest country in South America
