"选择权契约" can be translated as "option contract" in English.
In financial and legal contexts, an "option contract" refers to an agreement that gives the holder the right, but not the obligation, to buy or sell an underlying asset at a specified price within a certain time frame. This aligns with the concept of a "选择权契约" (xuǎn zé quán qì yuē), which typically implies a contractual arrangement granting a party the choice or option to take a particular action under certain conditions.