4) The short run is the time frame _-_ OA) during which the quantities of all resources are fixed. OB) that is less than a year. OC) during which the quantities of some resources are fixed. OD) during which the quantities of all resources are variable.

In economics, the short run refers to a period where some factors of production are fixed while others can be varied. This means businesses can adjust their output by changing variable resources like labor or raw materials but cannot alter fixed resources like factory size or equipment immediately. In real life, think about a restaurant. If demand suddenly spikes, the owner can hire more waitstaff and buy extra ingredients quickly, but they can’t immediately expand the kitchen or dining area until they plan for the long term. So, maximizing short-term adjustments is key to keeping operations smooth and profits flowing!