Nowadays，we don't have enough resources to use．So it's everyone's duty to save them for the future．To save resources，we should     ．（　　）

①throw away a pencil without completely using it

②collect waste things for recycling

③go to school by bike instead of by car

④turn off the tap while brushing our teeth

⑤keep the lights on day and night．

A．

①②⑤

B．

②③④

C．

②④⑤