Final answer:
An intra-sector system refers to a collection of multiple components within the same sector. So, the option is A.
Step-by-step explanation:
In essence, it signifies a collection of entities, operatives, or activities that function within the same domain or industry. For instance, within the financial sector, an intra-sector system might consist of various banks, insurance companies, and investment firms that all operate under the broader financial services umbrella.
It is important to understand that these systems can be complex with numerous interdependent components. The cohesion and interactions within these components are critical for the functionality and efficiency of the entire sector. In contrast, option B refers to a specific subway line within the Metropolitan Transportation Authority, which is unrelated to this concept. Option C, the housing crisis, is a broader socioeconomic issue not limited to intra-sector dynamics, and option D, a street, is a physical infrastructure element that does not typically represent an intra-sector system.
An MTA subway line (B) is a component in the transportation infrastructure of a city, the housing crisis (C) refers to a situation where affordable housing is scarce and out of reach for many people, and a street (D) is a paved public thoroughfare in a built environment.
Therefore, A is the correct option.