Final answer:
Language is the sociocultural factor among the options given, reflecting its role in society's culture and communication.
Step-by-step explanation:
The question regards sociocultural factors in the international environment. Sociocultural factors are elements that reflect the social and cultural aspects of a society. Among the choices provided, language is a sociocultural factor. Language represents a key aspect of a society's culture and communication and has a significant impact on international business, education, and social interactions. In contrast, exchange rates, tariffs, taxes, and quotas relate to economic considerations, while per capita income and infrastructure tend to be economic indicators that can also influence and reflect a society's standard of living.