Answer:
4) "Everyone in Spain speaks at most 9 languages."
Step-by-step explanation:
A negation is a statement that contradicts the original statement. Since the original statement regards people in Spain, options 2, 5, 6 and 7 can be ruled out as they refer to speakers outside of Spain.
Evaluating the remaining statements.
1) "Everyone in Spain speaks at least 10 languages."
If that is true, then someone in Spain speaks at least 10 languages, it doesn't negate the original statement.
3) "There is someone in Spain who speaks at most 9 languages."
It only refers to one specific individual, it doesn't negate the original statement.
4) "Everyone in Spain speaks at most 9 languages."
This means that nobody in Spain speaks more than 9 languages, contradicting the original statement.
The answer is statement 4.