Concept:Language register refers to how language changes based on the situation or context in which it is used.Explanation:Language is not fixed; it varies with different situations and purposes. The same person uses different language with family, colleagues, or a boss. This variation is called register. It depends on the relationship between speakers and the setting. For example, informal language at home becomes more formal at work. Thus, language register is the variation according to context, not just social class or grammar rules.Answer:B. The variation in language according to the context in which it is used.