Which of the Following Was a Measurable Objective for the 'Earth

Which of the following was a measurable objective for the 'Earth Hour' campaign?

A) Length of time that consumers' lights would be switched off
B) Percentage of Australian consumers who have a favourable opinion of the campaign's partners
C) Percentage of people who believe global warming is exaggerated
D) Number of people who reduce their use of electricity
E) Number of people who switch off their lights for one hour at a set time