Final Answer:
The ability to purchase a product is a function of Buying power.Thus, the correct answer is a) Buying power.
Step-by-step explanation:
The ability to purchase a product primarily revolves around "buying power" (option a). Buying power refers to an individual or entity's financial capacity to acquire goods or services. It is directly linked to the available financial resources and influences the ability to make purchases.
While desire (option b), willingness (option c), authority (option d), and needs (option e) are essential factors that contribute to the decision-making process of purchasing, they do not solely determine the ability to acquire a product.
Desire signifies the wish or craving for a product, willingness relates to the readiness to make a purchase, authority pertains to the legal right to buy, and needs refer to the necessities or requirements of an individual or market.
However, without the necessary financial resources or buying power, the desire, willingness, authority, or needs to purchase a product cannot be realized. Buying power, influenced by income, savings, credit availability, and overall financial situation, remains a crucial factor enabling individuals or entities to convert their intentions or necessities into actual purchases.
Therefore, while other factors contribute to the decision-making process, buying power fundamentally determines one's ability to make a purchase by providing the necessary financial means.
Thus, the correct answer is a) Buying power.