Answer: optimal level of arousal
Explanation: arousal theory stated that individuals has different levels (grades) or arousal. Mostly when our arousal level is high, we usually do that thing that will help bring it down.optimal arousal refers to the maximum level of arousal or energy that which mental boost or encouragement of physical activities, learning and others. It is the high energy or readiness to do a particular thing. Arousal can be like to agitation,stress, motivation, drive and attention. Mostly drive or arousal among human differ what really works for you, motivate you or even have all your attention may be different from mine or higher level of your arousal is different from mine which may be of lower level of arousal.
Arousal is simply what's makes us acts,think or even do things in any way we deem fit.
Out of the choices given, All economies must determine how to allocate their scarce resources is the same as the "all economies must decide what to produce." They are only written different and the one sentence gives more detail.
