Which one of the following series contains only electrophiles?

In each of the following groups,which is the strongest (best) nucleophile?
$(I)$ $(1)$ $H_3C-O^-$,$(2)$ $CH_3CH_2O^-$,$(3)$ $H_3C-S^-$ in $CH_3OH$
$(II)$ $(1)$ $OH^-$,$(2)$ $H_2O$,$(3)$ $NH_2^-$ in $DMF$
$(III)$ $(1)$ $(CH_3)_2CH-O^-$,$(2)$ $O^-$,$(3)$ $CH_3O^-$ in $DMSO$

The products $(A)$ and $(B)$ in the following reaction are:

Match the items in Column-$A$ with the appropriate items in Column-$B$:

Column-$A$	Column-$B$
$(1)$ Free radical	$(A)$ Lewis base
$(2)$ Electrophile	$(B)$ Electrically neutral
$(3)$ Nucleophile	$(C)$ Octet complete
	$(D)$ Lewis acid
	$(E)$ Odd number of electrons
	$(F)$ Incomplete octet

What is the decreasing order of basic strength for the following species: $\mathop O\limits^\Theta H, \mathop N\limits^\Theta H_2, HC \equiv \mathop C\limits^\Theta, CH_3 - \mathop C\limits^\Theta H_2$?

What are electrophiles and nucleophiles? Explain with examples.