Final answer:
General Motors and Toyota formed a joint venture called NUMMI to build cars in California.
Step-by-step explanation:
The correct answer is d) Joint venture. When General Motors and Toyota created a separate organization called New United Motor Manufacturing, Inc. (NUMMI) to build cars in California, they formed a joint venture. A joint venture is a business arrangement in which two or more companies come together to form a new entity for a specific purpose or project. In this case, General Motors and Toyota partnered to build cars together.