A major impediment to wide acceptance of electric vehicles even on the part of people who use their cars almost exclusively for commuting is the inability to use electric vehicles for occasional extended trips. In an attempt to make purchasing electric vehicles more attractive to commuters, one electric vehicle producer is planning to offer customers three days free rental of a conventional car for every 1,000 miles that they drive their electric vehicle.

Which of the following, if true, most threatens the plan's prospects for success?

【选项】The relatively long time it takes to recharge the battery of an electric vehicle can easily be fitted into the regular patterns of car use characteristic of commuters.