Why would the mixing of salt water with fresh water be considered an example of increased entropy?*

When the salt water is mixed with the
freshwater the salt is able to attract
more heat or absorb it. The salt also
has the ability to lower the water's
freezing point. With all this it increases
the temperature which increases the
entropy. The constant mixing of salt
and freshwater causes disorder in
Mono Lake, which results in a higher or
increased entropy

When the salt is mixed

Yes, the correct answer is b.