The correct statements are:

• (A) Depreciation is a flow concept: Depreciation is the gradual decrease in the value of an asset over time. It is measured as a flow over a period (e.g., annually).
• (B) Money supply is a stock concept: Money supply represents the total amount of money in circulation within an economy at a specific point in time. It's a stock variable measured at a particular moment.

Incorrect Statements:

• (C) Investment is a stock concept: Investment is a flow concept. It refers to the spending on new capital goods (machinery, equipment, etc.) over a period of time.
• (D) Depreciation is an annual allowance for wear and tear of a consumer good: Depreciation primarily applies to capital goods (assets used in production), not consumer goods.

In summary: Depreciation and investment are flow concepts, while money supply is a stock concept.