option在此的语义为： a right to buy or sell something for a specified price during a specified period of time。此时option后接to do不定式或on介词短语作限制性定语。例如《韦氏高阶》例句：
Employees will each be granted/given options to buy 1,000 shares of company stock.
The company has taken an option on some land nearby. [=it has obtained the right to buy the land at a particular price]
