Final answer:
H. J. Heinz Company was involved in a vertical conflict with British supermarkets that preferred their own private brands over Heinz products, affecting Heinz's market presence and sales.
Step-by-step explanation:
When supermarkets in Great Britain promoted and displayed private brands at the expense of the Heinz brands, the type of conflict H. J. Heinz Company found itself involved in was a vertical conflict. This type of conflict occurs between different levels within a distribution channel, in this case between the manufacturer, H. J. Heinz, and the retailers (supermarkets). The supermarkets prioritized their own private labels, which likely negatively impacted Heinz's sales and shelf presence. This differs from a horizontal conflict, which would involve conflicts at the same level such as between competing manufacturers or retailers.