Final answer:
The correct answer to the student's question about the firm's marketing mix is 'e. people,' which is not one of the original four Ps of the marketing mix: product, price, promotion, and place.
Step-by-step explanation:
The question at hand concerns the components of a firm's marketing mix, traditionally known as the four Ps: product, price, promotion, and place. In the context of the original four Ps, 'people' is not considered a core decision area. The commonly accepted elements of the marketing mix do not include 'people.' Instead, 'people' is associated with an extended marketing mix or services marketing mix, often referred to as the seven Ps.
This expanded framework includes people, process, and physical evidence in addition to the original four Ps. Therefore, in the context of the basic marketing mix, the correct response to the question is 'e. people,' as 'people' is not one of the core decision areas in the traditional four Ps.