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 17 to 23.

People travel for a lot of reasons: Some tourists go to see battlefields or religious shrines. Others are looking for culture, or simply want to have their pictures taken in front of famous places. But most European tourists are looking for a sunny beach to lie on.

Northern Europeans are willing to pay a lot of money and put up with a lot of

inconveniences for the sun because they have so little of it. Residents of cities like London, Copenhagen, and Amsterdam spend a tot of their winter in the dark because the days are so short, and much of the rest of the year in the rain. This is the reason why the Mediterranean has always attracted them. Every summer, more than 25 million people travel to Mediterranean resorts and beaches for their vacation. They all come for the same reason, sun!

The huge crowds mean lots of money for the economies of Mediterranean countries. Italy’s 30,000 hotels are booked solid every summer. And 13 million people camp out on French beaches, parks and roadsides. Spain’s long sandy coastline attracts more people than anywhere else. 37 million tourists visit yearly, or one tourist for every person living in Spain.

But there are signs that the area is getting more tourists than it can handle. The

Mediterranean is already one of the most polluted seas on earth. And with increased tourism, it’s getting worse. The French can’t figure out what to do with all the garbage left by campers around St. Tropez. And in many places, swimming is dangerous because of pollution.

None of this, however, is spoiling anyone’s fun. The Mediterranean gets more popular every year with tourists. Obviously, they don’t go there for clean water and solitude. They tolerate traffic jams and seem to like crowded beaches. They don’t even mind the pollution. No matter how dirty the water is, the coastline still looks beautiful. And as long as the sun shines, it’s still better than sitting in the cold rain in Berlin, London, or Oslo.

According to the passage, what do people use a diagnostic machine for A. To make