Final answer:
Trajan was given the title of 'optimus princeps' by the ancient Romans, reflecting their high regard for his exemplary leadership, making the correct answer c) Optimus.
Step-by-step explanation:
Trajan, officially known as Marcus Ulpius Traianus, was a Roman Emperor who reigned from 98 to 117 CE. He was well-regarded for his leadership and military accomplishments, particularly in the wars against Dacia. The ancient Romans held him in such high esteem that they gave him the honorific title of optimus princeps, which translates to "the best ruler." This designation highlighted his virtues and capabilities as an Emperor during a period often considered the peak of Roman prosperity and stability. Therefore, the correct answer to the question regarding Trajan receiving an honorific name is c) Optimus.