Explanation:

- Option 1: Zero

- If money had a utility of zero, it would mean it holds no weight in consumption decisions, which is impractical.

- Option 2: Less than one

- A utility value less than one implies that money holds a small role, which doesn't reflect its necessity in balancing purchasing priorities.

- Option 3: More than one

- A value greater than one would overemphasize money, overshadowing the marginal utilities of other goods.

- Option 4: One

- This means that money is a consistent measure of value, ensuring that decisions pivot on the added gains per unit of currency spent.

- The law of equi-marginal utility fundamentally assumes the price of money as one for uniformity in marginal utility calculations.