Which sentence could best be added after sentence 6? (6) These electric cars could help us to be less dependent on other nations for our energy. OA. Traditional, gasoline-consuming cars must be driven regularly to keep the battery charged. OB. Our neighbor to the north, Canada, is both an importer and an exporter of petroleum products. OC. Last but not least, plug-in hybrids emit less pollution and are better for our environment. OD. The technology for electric vehicles has actually been around for many, many decades.​