what is your question exactly I might be able to help if you have a question
Many primary sources cannot be understood because of the language or they way they have written it. We can't always understand it because its from a culture completely different from our own. Reading primary sources requires your his historical imagination.
For this case we have the following functions:

We must find the product of both functions:

We apply distributive property term to term:

We add similar terms:

Answer:
Option B
President Ronald Reagan rejected the theory of Keynesian economics, this theory proposed by John Maynard Keynes, embodied in his work General Theory of Employment, Interest and Money, published in 1936 in response to the Great Depression of 1929, the central principle of this school of thought is that state intervention can stabilize the economy, Keynesianism is one of the best-known economic theories, its main characteristic is that it supports interventionism as the best way out of a crisis and as a mechanism to stimulate demand and regulate the economy in times of depression.