In a currency union, one major challenge is the varying levels of development among regions. What was the key difference between European Union's assistance to Greece during the debt crisis and the US's assistance to Alabama on a daily basis?

a	Some of the EU members share a common currency, the euro, whereas the US does not have one.
b	The EU used capital control, limiting the financial help flowing to Greece, whereas the US allows capital mobility among the states to invest in Alabama.
c	The EU gave Greece loans expecting a payback while the US uses fiscal transfer without any expectation of returns.
d	Greece enjoys monetary autonomy whereas Alabama does not.