Final answer:
Caskey Company and Holland Inc. have created a horizontal complementary strategic alliance to share marketing resources and reach a similar client base.
Step-by-step explanation:
The strategic alliance formed between Caskey Company and Holland Inc., in which they agree to share marketing resources to attain a similar client base, is known as a horizontal complementary alliance. This type of alliance occurs between firms that operate at the same level within an industry and produce similar kinds of products or services. By sharing marketing resources, these companies aim to grow larger, improve efficiency, expand their product offerings, or achieve other synergistic effects without going through a merger or acquisition.