Technological progress has made it possible for firms such as Apple and Alivecor to develop small electronic devices, including smartwatches, smartphones, and products that can be attached to the smartwatches and smartphones, to serve consumers who

have become more health conscious and wish to monitor various health conditions. These firms are reacting to which of the three key economic ideas?
A) people are rational B) people respond to economic incentives
C) firms attempt to maximize revenues D) optimal decisions are made at the margin

B