Final answer:
The constitutional question involves whether the existence of the Federal Reserve is constitutional or not, with different interpretations and debates regarding its establishment and role.
Step-by-step explanation:
The constitutional question involved here is whether the existence of the Federal Reserve is constitutional or not.
Option A states that the Constitution explicitly forbids establishing a central bank, but there is still a debate about whether the Federal Reserve System is a central bank or not.
Option B states that the Constitution does not directly discuss a central banking system, but the Fed's constitutionality was confirmed by the Supreme Court.
Option C states that the Constitution allows for the creation of a central banking system only if it remains fully independent of the government, which the Supreme Court has upheld that the Fed meets this criteria.
Option D states that the Constitution explicitly calls for the establishment of a central bank, but there is still a debate about whether the Federal Reserve System is a central bank or not.