The correct answer is C) Hotels.
The opening of hotels has not contributed to the increase of Istanbul’s population.
The construction of hotels is good for tourist who visits the city of Istambul for 4 or 5 days. That represents a benefit for the touristic activity in the country. But tourist comes and go, so the opening of hotels has not contributed to the increase of Istanbul’s population. To increase the population, people need to stay in the city for a long time not temporarily. They need to stay on a permanent basis.