Final answer:
The establishment of Constantinople led to the decline of the Western Roman Empire by focusing resources, political, and military attention on the East, leaving the West vulnerable and fostering divisions between the two halves of the Empire.
Step-by-step explanation:
The establishment of Constantinople as the new center of the Empire contributed to the acceleration of the Western Roman Empire's decline principally through the relocation of political and military focus, which left the Western provinces vulnerable. This is option B in the student's question. The shift of the capital to Constantinople shifted the empire's geographic focus eastward, resulting in the West's neglect.
The East, being the richer part, benefited from efficient bureaucracy and tax-collecting systems, which further attracted resources and attention away from the West. Moreover, the creation of Constantinople as the center and the establishment of the Eastern Orthodox Church fostered cultural and administrative divisions between the Eastern and Western halves of the empire.