Answer:
e. Buyers
Explanation:
As per Michael Porter's 5 forces to assess industry attractiveness, following are the five forces:
1. Buyer power
2. Supplier power
3. Threat of substitutes
4. Threat of new entrants
5. Competitive Rivalry
As per the given information, the students represent the buyer power with respect to their negotiation or bargaining power. This means the influence and control buyers exercise over price of products (textbooks) here.
In the given case, the supplier power appears more domineering since buyers, the students have no other option but to buy the updated textbooks beyond a period of time as those books have been suggested by the professor.