Banks make a profit primarily by buying stocks and bonds, issuing loans to customers, purchasing properties, and buying the rights to loans. Opening checking accounts and starting new businesses do not directly contribute to a bank's profit. Therefore, the correct options that banks use to make a profit are C, D, E, and F.
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Banks make a profit through various investments such as buying stocks and bonds, purchasing real estate, issuing loans, and buying the rights to loans. They do not directly profit from opening checking accounts or starting new businesses. Profit generation revolves around lending and investing rather than risks associated with new ventures. ;