A growing number of U.S. bike riders are attracted to electric bikes for convenience, health benefits and their fun factor. Although ebikes first appeared in the 90s, cheaper options and longer-lasting batteries are breathing new life into the concept.

        Established bike companies and startups are embracing ebikes to meet demand. About 34 million ebikes were sold worldwide last year, according to data from eCycleElectric Consultants. Most were sold in Europe and China, where the bikes already have exploded in popularity. Recently, the U.S. market has grown to 263,000 bikes, a 25% gain from the prior year.

        The industry is benefiting from improved batteries as suppliers over the years developed technology for laptops, smartphones and electric cars. In 2004, the price of batteries used on ebikes fell, spurring European sales.

        But lower cost options are emerging, too. This month, three U.S. bikeshare companies, Motivate, LimeBike and Spin, announced electric bicycles will be added to their fleets. New York-based Jump Bikes is already operating an electric bikeshare in Washington, D.C., and is launching in San Francisco Thursday. Rides cost $2 for 30 minutes.

        The system works like existing dockless bikeshare systems, where riders unlock bikes through a smartphone app. “This is the beginning of a long-term shift away from regular pedal (踏板) to electric bikes,” said Jump Bikes CEO Ryan Rzepecki. “When people first jump on an ebike, their face lights up. It’s exciting and joyful in a way that you don’t get from a regular bike.”

        Two years ago, CEO Chris Cocalis of Pivot Cycles, which sells high-end mountain bikes, found that U.S. bike shops weren’t interested in stocking ebikes. Some retailers warned Cocalis that they’d drop the brand if it came out with an electric bike.

        Now that sales are taking off, the vast majority of bike dealers are asking Cocalis when he’ll make an ebike available. “There’s tremendous opportunity to get a generation of people for whom suffering isn’t their thing,” Cocalis said. “Ebike riders get the enjoyable part of cycling without the massive suffering of climbing huge hills.”

解析：A。根据题干中的Chris Cocalis可定位至倒数第一、二段。倒数第二段讲到，两年前，销售高端山地车的Pivot Cycles公司首席执行官克里斯•科卡利斯发现，美国的自行车商店对电动自行车备货不感兴趣。一些零售商警告科卡利斯，如果Pivot Cycles公司推出电动自行车，他们将放弃该品牌。由此可知，克里斯•科卡利斯无法更早地开发电动自行车是由于零售商拒绝销售电动自行车，A项符合题意，故为正确答案。

错项排除：原文中并没有提到传统自行车的高额利润和电动自行车骑行的风险问题，因此排除B和C两项。原文中提到克里斯•科卡利斯在销售高端山地车的Pivot Cycles公司担任首席执行官，但并没有说他专注于销售昂贵的山地自行车，而且这也不是阻碍他开发电动自行车的原因，D项为过度引申，排除。