For typical Fischer and Schrock carbenes, consider the following statements
\[ \begin{array}{l} \text{A. Oxidation state of metal is low in Fischer carbene and high in Schrock carbene} \\ \text{B. Auxilliary ligands are } \pi\text{-acceptor in Fischer carbene and non } \pi \text{ acceptor in Schrock carbene} \\ \text{C. Substituents on carbene carbon are non } \pi \text{ donor in Fischer carbene and } \pi \text{ donor in Schrock carbene} \\ \text{D. Carbene carbon is electrophilic in Fischer carbene and nucleophilic in Schrock carbene} \end{array} \]