Infrastructure consists of basic facilities and systems that serve the country, city or some specific area, including the services and facilities necessary for the functioning of the economy. Generally speaking, the infrastructure consists of all physical components of interconnected systems that enable the goods and services necessary for the maintenance and improvement of social living conditions. There are two types of infrastructure, hard and soft. Hard refers to the physical networks necessary for the functioning of modern industry, such as railways, roads, bridges, etc. Soft refers to all institutions that maintain the state's economic, social, health and cultural standards, such as educational programs, parks, recreational facilities, emergency services, etc.
The answer is: d.