Answer:
Option A. Competitors, a single
Since horizontal integration is the process of acquiring and merging with Competitors, it is the type of corporate strategy that can improve a firm's strategic position in a Single industry/industries.
Step-by-step explanation:
In a horizontal integration, the company acquires or merges its business with the competitor in same line of business to control the competition and market decisions. This helps the company to take most of the control of the single industry by increasing its bargaining price due to access to wider number of resources and product knowledge which enables the group to manufacture a differentiated product.
Hence the option A is correct.