38. 某船在南緯，設其緯度L；若該船向北航駛d浬，又向東航駛d浬，再向南航駛d浬，又 向西航駛d浬，並假設此船未跨過赤道；則請問出發點至到達點間的經度差為下列何者 ？
(A)d [sec L- sec (L- d)] E
(B)d [sec L- sec (L- d)] W
(C)d [sec L- sec (L+ d)] E
(D)d [sec L- sec (L+ d)] W

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統計： A(4), B(8), C(2), D(0), E(0) #3014182