题目内容：

It's believed that travelling makes a full man. However, travelling with friends or travelling alone is a question. Which of the following can help you decide to set out on your trip alone?

①It helps to improve your ability to solve problems.

②You may feel lonely.

③It makes you learn to be responsible for everything.

④You'll get more freedom(自由) to do the things you like.

⑤You don't have to worry about your safety.

A.②③④ B.①③④ C.②④⑤