Final answer:
Each Gospel was meant as a religious and instructional text for early Christian communities, serving as a guide and a unifying narrative for believers in the first century.
Step-by-step explanation:
By saying each Gospel was sent to a Christian community in the first century, it means that the Gospels were meant as religious and instructional texts for early Christian communities (Option C). The four Gospels - Matthew, Mark, Luke, and John - were composed after Jesus's death based on oral traditions and memories of the apostles and early Christian leaders. Written approximately around 90 CE, they provided guidance for believers, helped unify the community around a common narrative, and were instrumental in the teaching and spread of Christianity during that time. These texts were not just meant for historical documentation (Option A), nor were they sent to Jewish communities (Option B), and they definitely were not composed in the 4th century (Option D).