The word their” in paragraph 2 refers to .

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the Questions from 28 to 32.
More and more people are choosing to take a gap year between finishing school and starting university.
Alternatively, they may decide to take a gap year between graduating from university and starting a career, feeling the need for some time out before joining the rat race. Most students use the time as an opportunity to travel. The idea of travelling to an area that is new and foreign appeals as possible appeals greatly.
A large percentage of gap-year students have have wealthy parents who can easily subsidize their travel. Others have to save up before they go, or look for some form of employment while travelling. For example, they may work on local farms or in youth hostels. By doing so, they not only earn money, they are likely to meet local people and acquire some understanding of their culture.
There are some students who choose to work for the whole of their gap ear. A number may decide to get work experience, either at home or abroad, in an area which they hope to make their career, such as medicine or computers. A large proportion of students are now choosing to work with a charity which arranges voluntary work in various parts of the world. The projects provide hands-on experience of a very varied nature, from teaching to helping build roads or dams.
The gap year is not just an adventure. Young people can benefit greatly from encountering new and varied experiences and from communication with a wide range of people. Perhaps most importantly, gap-year students have to learn to stand on their own two feet.
(Adapted from Thematic Vocabulary & Comprehension by Betty Kirkpatrick and Rebecca Mok)