Railroad crossing signs come in two kinds of shapes which are: "Circle and crossbuck."
This is evident in the fact that Circle is used Railroad crossing signs to represent an advanced warning sign.
While the Crossbuck is used as the Railroad crossing sign to represent the grade crossing signs.
This is based according to the traffic sign made by the United States.
Hence, in this case, it is concluded that the correct answer is option A. "Circle and crossbuck."
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