Let's analyse the alternatives:
First of all, we need to consider 0 (zero) that is not positive nor negative number.
First one: we have a negative number --> the opposite is a positive number --> the opposite of the positive number is a negative number. So this sentence is TRUE.
Second one: The absolute value of a number is always positive so the absolute value of 4 is equal to 4 and the opposite value of the absolute value of 4 is -4 so it is not the same. So this sentence is False.
Third one: For all numbers instead of 0 (zero) the absolute values must be positive, but once 0 is a number and we can not consider it positive or negative this sentence is False.
Fourth one: The absolute value of a negative number is a positive number and the value of the opposite number of this negative number is also a positive number so this sentence is TRUE.
Fifth: Well, once zero has no opposite, this sentence is FALSE.
Sixth: We already know there is a number (zero) that is not positive or negative, so this sentence is FALSE.