2. In the UK students have special celebration

Обоснование: В тексте говорится: "Unfortunately, the end of secondary education in the U.K. is not marked by any sense of celebration, like in other countries, for example, like the USA where students graduate at the age of 18 and have a fancy ball. (In the UK you have to wait until you finish college or university before you can have that privilege). In the UK you just 'finish school!'" Это означает, что празднование происходит по окончании школы, а не университета или в определенном возрасте.

Ответ: b) when they finish school.