Step 1: Understanding the Concept:
Money Income (Nominal Income) represents the value of output measured at current market prices.
Step 2: Detailed Explanation:
Mathematically, nominal money income ($Y_m$) is calculated as:
\[ Y_m = P \times Q \]
Where:
- $P$ is the general price level.
- $Q$ is the real physical output of goods and services.
From this relationship, money income can increase under several conditions:
1. If $P$ increases while $Q$ remains constant (Statement A).
2. If $Q$ increases while $P$ remains constant (Statement B).
3. If both $P$ and $Q$ increase, or at least one of them increases (Statement C).
Conversely, a fall in the price level (Statement D) would cause money income to decrease, assuming output does not rise disproportionately.
Therefore, statements A, B, and C are correct descriptors of conditions that lead to an increase in money income.
Step 3: Final Answer:
The correct statements are A, B, and C, matching Option (C).