Which description fits an immediate precursor?

An immediate precursor is specifically defined as a chemical substance that is essential in the manufacturing process of controlled substances, typically acting as an intermediary step. This definition aligns directly with the characteristics of option B, which refers to a chemical intermediary in manufacturing controlled substances. Such substances are not themselves illegal drugs but are critical in the synthesis and preparation of those substances, making their regulation important in the context of drug enforcement and public safety.

The other options, while potentially related to substances one might find in various contexts, do not fit the specific legal and chemical definition of an immediate precursor. For example, a substance used for cooking, a primary food ingredient, or a common household item may not have any relevance or direct connection to the production of controlled substances or be regulated in the same manner. Hence, they do not meet the criteria necessary to be categorized as immediate precursors. The focus on chemical intermediaries in manufacturing controlled substances highlights the importance of recognizing and controlling these compounds to prevent the illicit drug trade.