Which of the following statements is true about the PKN model and the KGD model? A: PKN model is suitable for the fracture with a long fracture length greater than the fracture height. B: KGD model is suitable for the fracture whose height is far greater than its length. C: The plane assumption of PKN model is the direction of fracture width and height. D: The plane of KGD model is assumed to be joint width and seam length direction.

关于PKN模型和KGD模型，以下表述正确的是？ A: PKN模型适用于缝长远大于缝高的裂缝 B: KGD模型适用于缝高远大于缝长的裂缝 C: PKN模型平面假设是缝宽和缝高方向 D: KGD模型平面假设是缝宽和缝长方向