Answer: b. Tightened audit regulations and controls.
Details:
Corporate fraud in the 2000-year era, also known as the "Dotcom bubble" made many investors lose vast amounts of money, while many unethical corporate executives made off with "bandit-like" profits.
Consequently, two lawmakers, Sarbarnes and Oxley proposed a bill for financial reform and accountability by corporations. The bill was signed into law in 2002, and it demands tightened accounting, auditing, financial responsibility, and accountability toward investors.
Hopefully, this law will prevent disasters such as Enron, Worldcom, Tyco and many others from "ripping off" investors in the future.