When can a European style option be exercised?

A European style option can only be exercised on the expiration date. This characteristic differentiates European options from American options, which can be exercised at any time before expiration. The design of European options means that the holder must wait until the specific expiration date to execute their right to buy or sell the underlying asset. This structure often affects the pricing and trading strategies associated with these options, as traders must consider the timing of market movements carefully.

The other options present scenarios that do not apply to European style options: exercising at any time before expiration or on specific dates as set by the holder does not align with the inherent rules governing these contracts. Thus, the correct understanding of European options centers around the limitation of exercise to the expiration date.