Answer:
1. b. a single-party government.
A single-party government is likely to only allow its citizens to hold one particular political opinion. This is because any dissenting opinion is likely to weaken their control over the population. Therefore, countries with a single-party government are usually not considered functioning democracies.
2. b. forms of currency
It is unlikely that currency (the US dollar) will not remain uniform across all states. Having different types of currency would make commerce and trade difficult across state lines. Moreover, it goes against the primary purposes of the Federal Reserve System.