The answer to this is letter D. The Securities Act Exchange of 1934 is created by SEC. Its main goal is to regulate the secondary market. This was created back then in order to make people trust the financial market again. The financial market experienced a crash in 1929 so people were a bit wary of it.
This is considered to be a successful act but only because it worked well together with the Securities Act of 1933. The SEC is responsible for all of those that are under the security industry. By doing this, it is more possible for people to see that they can trust the market more because the figures can be manipulated less.