g explain why a consumer will never choose to consume a combination of goods where their indifference curve is upward sloping.

The correct answer is: Because that action will violate the basic principles of the preferences of the consumers.

Explanation:

To begin with, the microeconomic theory, the consumers have preferences and to that preferences there are simple conditions and principles that have to be respected. Those conditions establish that a consumer have preferences that are "complete", "transitive" and that they prefer much more of a good product that less of that product. If a consumer will choose to consume a combination of goods where their indifference curve is upward sloping then the rules will be violate and that will not respect the logic of the economy's theory because it is stated that the indifference curves are convex.  

answer; lags, push the econ below the natural level of output;