Final answer:
Gatorade advertising its sports drinks to elderly consumers is an example of market development, a product-market strategy that involves expanding an existing product line.
Step-by-step explanation:
This type of product-market strategy is b) Market Development. Gatorade advertising its sports drinks to elderly consumers is an example of expanding their existing product line, which is a characteristic of market development. By targeting a new demographic, Gatorade is seeking to increase its market share and reach a new customer base. This strategy is aimed at growing the overall market for its products.