下列哪个语句在python中是非法的（ ）

A、x = y = z = 1 | x = (y = z + 1) | x, y = y, x | x
+=
y
B、x = y = z = 1 | x = (y = z + 1) | x, y = y, x | x
+=
y
C、x = y = z = 1 | x = (y = z + 1) | x, y = y, x | x
+=
y
D、x = y = z = 1 | x = (y = z + 1) | x, y = y, x | x
+=
y