Do oranges gain or lose vitamin C after being picked

Do oranges gain or lose vitamin C after being picked?
When we squeeze the oranges to
make orange juice, it loses vitamin
C.
Vitamin C is lost when the
orange skin is removed.
It loses vitamin C when it is
heated.
It loses vitamin C when we add
fertilizers to it when it is
growing.
It does not lose vitamin C
after picked but will if salt is
present.
When we slice the oranges into
smaller pieces, it loses its
vitamins.
They will decay after a long period of
time and might lose the vitamin C
inside.
It loses vitamin C after a
period of time.
They don't lose vitamin C.
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