Which of the following statements is true concerning the consumption function?

The correct answer is **all of the above**.

Here's a brief explanation for each point:

1. **It slopes upwards**: The consumption function typically shows a positive relationship between consumption and income, meaning that as income increases, consumption also tends to increase.

2. **Its slope equals the MPC (Marginal Propensity to Consume)**: The slope of the consumption function represents the MPC, which is the change in consumption resulting from a change in disposable income.

3. **It represents the direct (positive) relationship between consumption spending and the level of real disposable income**: The consumption function illustrates how increases in real disposable income lead to increases in consumption spending.

Thus, all statements are true regarding the consumption function.