Designate the species (A) and (B) as electrophile ( E) or nucleophile (Nu) in the following reactions :
(a) `BEt_(3) +Me_(2)ddotO:rarrMe_(2)overset(o+)underset(..)(O)-overset(Theta)BEt_(3)`
(b) `CH_(2) =O +underset("Bisulphite ion")( :overset(Theta)SO_(3)Hrarr)underset(O^(Theta))underset(|)(CH_(2))-SO_(3)H`
( c) `C_2H_5C1 + :CH:^(Ө) rarrC_2H_5 -CN + C1^(Ө)`
(d)
( e) `CH_(3)-overset(o+)(CH)-underset(CI)underset(|)(CH_(2)) +CI^(Theta) rarr CH_(3) -underset(CI)underset(|)(CH)-underset(CI)underset(|)(CH_(2))`
(f) `:underset(..)overset(o+)NH_(2) +CH_(3)-C-=CH rarr CH_(3)-C -= C^(ddotTheta) +NH_(3)`

Explanation

`{:(Reaction, (a),(b),(c),(d),(e),(f)),(Species A,E,E,E,Nu,E,Nu),(Species B,Nu,Nu,Nu,E,Nu,E):}`.