The decreasing order of nucleophilicity among the nucleophiles
$\left( C \right),\left( B \right),\left( A \right),\left( D \right)$
$\left( B \right),\left( C \right),\left( A \right),\left( D \right)$
$\left( D \right),\left( C \right),\left( B \right),\left( A \right)$
$\left( A \right),\left( B \right),\left( C \right),\left( D \right)$
