Which one of the following definitions is a correct definition for symmetric set difference?
a.
The complement of B relative to A is denoted by A – B, and is the set of all those elements of A which do not belong to B.
More briefly A – B = {x | x ∈ A and x ∉ B}. This is also referred to as the difference between sets A and B.
b.
The symmetric difference between two sets A and B, written as A - B, is defined as the set of all elements that belong to B, but not to A.
More briefly, A - B = { x | x ∉ A and x ∈ B}
c.
The symmetric difference between two sets A and B, written as A + B, is defined as the set of all elements that belong to A or to B.
More briefly, A + B = { x | x ∈ A or x ∈ B}
d.
The symmetric difference between two sets A and B, written as A + B, is defined as the set of all elements that belong to A or to B, but not to both A and B.
More briefly, A + B = { x | x ∈ A or x ∈ B, but not both}