One way for a family to determine their energy use is by analyzing their electric bill each month. Most energy bills include a graph displaying energy use over the last 12 months. This allows people to consider their energy use and make adjustments if needed. Mr. Hernandez noticed his family's usage for this December was about the same as last December, even though they were gone on vacation for about a week and a half this year. Since they were not home for a portion of the month, he expected their energy usage would be significantly lower. He calls a family meeting to discuss how they can reduce their energy bill next December, when they take another family vacation.

Which idea will reduce their energy usage the most, while also reasonable to follow?
A) For the time they are home during December, cook meals outside on the charcoal grill instead of inside with the electric stove/oven.
B) When they return from their trip, leave the television off for a week, and hang clothes up outside to dry instead of using their electric dryer.
C) Before leaving for their trip, turn the central heating system off, along with lights and electrical household appliances that will not be in use.
D) While they are home in December, they can use candles instead of electric lights, and put their food in coolers so they can unplug their refrigerator.