Nucleophile is a species that should have

1.  a pair of electrons to donate

2.  positive charge

3.  negative charge

4.  electron deficient species


(a, c)
Nucleophile (nucleus-loving) is a chemical species that donates an electron pair to an electrophile (electron-loving). Hence, a nucleophile should have either a negative charge or an electron pair to donate. Thus, option (a) and (c) are correct.