Which of the following is not a definition of a stock?

The correct answer is based on the understanding of stock in a financial context. Stock represents ownership in a company and typically refers to shares, which can be quantified and traded. The other options involve definitions aligned closely with financial terminology or concepts directly related to stock.

When stating that "make something needed or wanted available to someone," it strays from the precise definition of stock in the context of finance. This phrase suggests a broader action or function that doesn't specifically pertain to the nature of stock as a financial instrument or ownership claim in a company.

On the other hand, the other definitions tie directly to stock in financial terms. The definition regarding the quantity of goods for sale pertains to inventory stock rather than financial stocks but still relates to the concept of stock. The notion of a share held by an individual investor is a direct description of stock ownership. Similarly, the total number of shares issued by a company directly addresses stock as it pertains to public offerings and shareholder equity. These definitions encapsulate the essence of stock as it is typically used in finance, making the fourth choice distinct from the others.