单选题 甲氧苄氨嘧啶的化学名为
   A．5-[[3，4，5-trimethoxyphenyl]methyl]-2，6-pyrimidine diamine
   B．5-[[3，4，5-trimethoxyphenyl]methyl]-4，6-pyrimidine diamine
   C．5-[[3，4，5-trimethoxyphenyl]methyl]-2，4-pyrimidine diamine
   D．5-[[3，4，5-trimethoxyphenyl]ethyl]-2，4-pyrimidine diamine
   E．5-[3，4，5-trimethylphenyl]methyl]-2，4-pyrimidine diamine