What type of contract gives investors the choice to buy or sell financial assets at a fixed price?

The correct answer is options because options contracts provide investors the right, but not the obligation, to buy or sell an underlying financial asset, such as stocks, at a predetermined price before or at the contract's expiration date. This flexibility allows investors to benefit from price movements without the commitment to execute the transaction, making options a popular choice for speculation and hedging purposes.

In contrast, futures contracts obligate the parties to buy or sell an asset at a specified future date and price, which does not offer the same level of discretion as an options contract. Contracts for difference are financial derivatives that allow traders to speculate on price movements between an opening and closing trade, but they do not directly provide the choice to buy or sell an underlying asset. Bonds are fixed-income instruments that represent a loan from the investor to the issuer and do not involve rights related to the buy/sell of financial assets at set prices.