21. The sizes of coupling constants are often related to the geometry of a molecule. In square planar Pt(II) complexes, J(Pt-P) is sensitive to the group trans to a phosphane ligand. Which of the following order is correct in terms of J(Pt-P)? (A) cis-[PtCl2(PEt3)2] ＞ trans-[PtCl2(PEt3)2] (B) [PtCl2(PEt3)2] ＜ [PtBr2(PEt3)2] (C) [PtCl2(PEt3)2] ＜ [Pt(NH3)2(PEt3)2] (D) [Pt(NH3)2(PEt3)2] ＜ [Pt(CH3)2(PEt3)2] (E) [PtBr2(PEt3)2] ＜ [PtH2(PEt3)2]