Answer:
a.
putting limits on the number of roughnecks allowed in nearby cities
Explanation:
<span>The economic civil war between eastern and western Ukraine is not a reason for the ongoing crisis, because said economic civil war doesn't really exist. Any economic conflicts existing are by and large between Ukraine and Russia, involving gas pipeline disputes. Meanwhile, the other choices all led to or built up to the current crisis. The surrender of nuclear weapons mandated by the Budapest memorandum led to the closer Ukraine-West ties that have Russia initiating its annexation to consolidate power and fulfill it's geopolitical ambitions, and the election and subsequent deposition of Viktor Yanukovych exacerbated the instability in the political environment, and furthered the divisions between the different regional and cultural areas, some of which have significant portions of Russian-sympathizing citizens.</span>
B. It was a challenge to decide how to divide forces and protect two coasts.
