I believe the answer is: Primary
For example, let's say take a look at normal employees at a company.
For most of them, the main reason they spend their time to do the job correctly is to obtain money/salary even though they have to spend their time being scolded by unlikable boss.
In the scenario above, we can say that money is the primary reinforcer for the target behavior
1.<span>nervous system
2.</span><span>cerebrospinal fluid</span>
<h2>
To appeal to the dissatisfied, multi-ethnic population of the Soviet Union.</h2>
A comment from the <em>History Channel</em> explains the situation in the USSR when Gorbachev was in power. "In 1985, even many of the most conservative hardliners realized that much needed to change. The Soviet economy was faltering and dissidents and internal and external critics were calling for an end to political repression and government secrecy." As far as the aim of Gorbachev's reforms, "The plan was for the Soviet Union to become more transparent, and in turn for the leadership of the nation and the Communist Party to be improved," according to <em>YourDictionary</em>.
In March 1985, Mikhail Gorbachev proposed policies of <em>perestroika </em>(restructuring) and <em>glasnost</em> (openness) in the Soviet Union. These seemed like policies that leaned in the direction of Western ways of economics and politics. <em>Perestroika </em>meant allowing some measure of private enterprise in the Soviet Union. <em>Glasnost </em>meant allowing a bit of freedom in regard to speech and publication. Gorbachev was not trying to get rid of the Soviet communist system. He actually was trying to prop it up and preserve it, because it was starting to have many problems sustaining itself, and there was too much dissatisfaction and dissent occurring among the country's people. But in the end, opening things up a bit with <em>perestroika </em>and <em>glasnost</em> policies pushed the USSR further in the direction of shedding the communist model under which it had lived for so long, and would begin to spell the end of the USSR.
The answer is b. Marital dissatisfaction
I hope that helped
