Which of the following strategies makes use of a guide?

An eco$-$app helps consumers identify which clothing brand has the smallest ecological footprint.

A tax on carbon makes it more expensive to produce gasoline, a cost that in turn impacts consumers who rely on gas stations.

Certain packaging makes it clear that its contents are toxic and should be disposed of at a hazardous waste handling facility.

A flashing red light and a fuel efficiency gauge on a car dashboard lets the driver know when they are driving inefficiently.