The number of nucleophiles in the following list is

$$ \mathrm{CH}_3 \mathrm{NH}_2, \mathrm{CH}_3 \mathrm{CHO}, \mathrm{C}_2 \mathrm{H}_4, \mathrm{CH}_3 \mathrm{SH} $$

From the following identify the groups that exhibit negative resonance $(-R)$ effect when attached to conjugated system

$$ \begin{array}{ccccc} \text { Formyl } & \text { Amino } & \text { Alkoxy } & \text { Cyano } & \text { Nitro } \\ A & B & C & D & E \end{array} $$