Which of the following statements about mutual funds is/are accurate? 1. Open-ended mutual funds allow investors to buy and sell units at any time based on the current NAV. 2. Closed ended mutual funds only allow transactions during specific intervals and are listed on stock exchanges. 3. Interval funds are a type of mutual fund that allows purchases and redemptions at predetermined intervals. 4. Exchange Traded Funds (ETFs) are a type of open-ended mutual fund that trades on stock exchanges like individual stocks.