Darpa is an agency that emerges technologies for the military. I would say B. investigate technologies. This is logical because they are working with technologies investigating how, where, and why they need to emerge in the first place.
In order to buy stock, you must go and find a stock broker. You do not always need a broker, but it is more convenient to have one to manage your stock. It also makes your life in the market easier. The broker will manage your shares and you tell him when you want to buy or sell your stock.
Answer:
The answer should be optics...
Explanation: