What `defaults` Actually Holds

def tag(item, tags=[]):
    tags.append(item)
    return tags

a = tag("a")
b = tag("b")
c = tag("c", tags=["x"])

Select all statements that are true after this code runs.

tag.__defaults__[0] contains "c" after the third call

a is b is True

tag.__defaults__[0] is a is True

c is a is True, since c was also produced by a call to tag

What `__defaults__` Actually Holds