Which statement best defines money laundering?

Money laundering is best defined by the process of disguising the illegal origins of funds. This involves a series of transactions that make illicitly gained money appear legitimate. The primary goal of money laundering is to obscure the source of the funds so that they can be used openly within the financial system without drawing suspicion.

In the context of the other options, accumulating wealth legally refers to the legitimate acquisition of assets and has no connection to illegal activities. Transferring money between accounts, on its own, is a regular banking activity and does not imply any criminal behavior unless the origin of the funds is illicit. Investing in legitimate businesses can be a subsequent step in the laundering process, but it doesn't define money laundering itself, as investments can also come from legal sources. Therefore, the definition that focuses on disguising illegal origins directly encapsulates the essence of what money laundering entails.