How Does the Eurozone Compare with the USA as a Possible

How does the eurozone compare with the USA as a possible optimal currency area (OCA) ?

A) The eurozone has a higher degree of labour mobility than the USA and labour law is much less restrictive in the eurozone than in the USA. On these measures, the eurozone is more likely to be an OCA than is the USA.
B) The eurozone has a lower degree of labour mobility than the USA and labour law is much more restrictive in the eurozone than in the USA. On these measures, the eurozone is less likely to be an OCA than is the USA.
C) The eurozone has a higher degree of labour mobility than the USA but labour law is much more restrictive in the eurozone than in the USA. On these measures, it is hard to judge whether the eurozone is more or less likely to be an OCA than is the USA.
D) The eurozone has a lower degree of labour mobility than the USA but labour law is much less restrictive in the eurozone than in the USA. On these measures, it is hard to judge whether the eurozone is more or less likely to be an OCA than is the USA.