Electrophiles are electron seeking species. Which of the following groups contain only electrophiles ?
A. `BF_(3), NH_(3), H_(2)O`
B. `AlCl_(3), SO_(3), NO_(2)^(+)`
C. `NO_(2)^(+), CH_(3)^(+), CH_(3)-overset(+)(C) = O`
D. `C_(2)H_(5)^(-), overset(*)(C_(2))H_(5), C_(2)H_(5)^(+)`