Which of the Following Statements Is TRUE

Which of the following statements is TRUE?

A) The nucleophile strongly influences both S_N1 and S_N2 reactions, while the nature of the nucleophile and the substrate structure are only important in S_N2 reactions.
B) The structure of the substrate is the only important factor for S_N1 reactions, while the nucleophile, leaving group, and the structure of the substrate are all important for S_N2 reactions.
C) For S_N2 reactions the only important factor to consider is the leaving group; for S_N1 reactions the structure of the substrate and the nature of the nucleophile are the most important factors.
D) The nucleophile and leaving group are both important in S_N2 reactions, while for the S_N1 reactions the leaving group and the structure of the substrate are very significant.
E) The nucleophile is not important for S_N2 reactions, but the structure of the substrate is very important; for S_N1 reactions the opposite is true.