The sentence that best explains why modern English reflects the influence of several languages is:
B. Between AD 500 and 1200, invaders from several countries conquered parts of Britain.
This statement is the most accurate because during the period mentioned, various groups such as the Romans, Vikings, and Normans invaded Britain. As a result of these invasions, the English language absorbed vocabulary, grammar structures, and linguistic elements from languages such as Latin, Old Norse, and Old French. This process of linguistic borrowing and influence over time contributed to the rich and diverse vocabulary and grammar of modern English.