(Figure: Graph) Use the Graph Below to Answer the Following

(Figure: Graph) Use the graph below to answer the following questions.
(A) What change caused the movement from point M to point L?
(B) What change caused the movement from point H to point G?
(C) If the item is hand-made antique-style wooden furniture, in what direction did labor costs change to cause the shift from point M to point G?
(d) If the item is wheat, in what direction did wheat farming technology change to cause the shift from point G to point M?