Final answer:
Increasing profits are most likely to occur at the introduction stage of the PLC when a new product or service is first introduced to the market and there is little competition.
Step-by-step explanation:
In a competitive market, profits result in the entry of new firms into the industry. This usually occurs when there is a high demand for a product and existing firms are making significant profits.
The entry of new firms increases competition, which can lead to a decrease in prices and potentially lower profits for all firms. Therefore, increasing profits are most likely to occur at the introduction stage of the Product Life Cycle (PLC), when a new product or service is first introduced to the market and there is little competition.