A city has a problem with litter on its streets. The city council is considering several measures to reduce the litter. Which measure to reduce litter would involve the use of 'nudge' theory? A banning the dropping of litter with heavy fines for people who ignore the ban B installing signs directing people to new litter bins and thanking them for using the bins C raising local tax and using the money to employ more people to pick up litter D removing all litter bins so that people have to take their litter home