Conair, a Manufacturer of Appliances and Personal Care Products, Adds

Conair, a manufacturer of appliances and personal care products, adds an electrical component to its curling iron that automatically switches off the curling iron when it has been idle for more than an hour. This improvement would best be classified as a(n) :

A) product line extension.
B) quality modification.
C) aesthetic modification.
D) brand extension.
E) functional modification.