Determine if the following scenarios are describing savings or investment. If they describe investment, which type of investment? Explain.

a. Amazon purchases $100 million worth of products from a Chinese manufacturer to add to its warehouse inventory.

b. SpaceX spends $5 million on writing and testing new code to improve its rocket stability.

c. The stock market experiences a major increase after the Federal Reserve announces that it won't raise the interest rate.

d. 1.2 million new homes were built in 2017 in the United States.