根据短文内容，从短文前方框内的选项中选出能填入空白处的最佳选项。

A. This e-bike is also very “smart”. B. So I’m very proud that we never gave up. C. The weight of this new e-bike is just 15kg. D. This material makes it light and friendly to environment. E. It included many years of research, development and failures.

E-bikes usually have a big problem—it is much heavier than common bikes. Recently, a Romanian company has solved this problem. （1） In fact, an adult can even lift it easily.

The reason for the low weight is the choice of material（材料）, which is quite unusual. It uses a frame（车架）made of bamboo. （2） What’s more, the bamboo frame also makes riding more comfortable, because it has good vibration damping（减震）.

（3） Your smartphone is connected to the e-bike. So you can check your riding information in real time through a special app on your smartphone.

The company manager said, “Creating the bikes was a hard journey. （4） To be honest, I really don’t remember how many times we had to face the failures（失败）.”

The manager continued, “But in the end, we succeeded. We have created a bike that is light-weight enough, strong enough and smart enough. （5） And now we have successfully developed these bikes to meet the needs of more people in cities.”