European Option VS American Option

First of all, what is an option？
Options grant their holder the right to buy or sell some underlying asset. Options are therefore contingent claims or derivative securities because their value depends on the underlying asset.

In the second, two kinds of options： Call option & Put option
A call option gives its holder the right to buy a specified number of the underlying asset by paying a specified exercise price or strike price.
A put option gives its holder the right to sell a specified number of the underlying asset by paying a specified strike price.

Third, European Option VS American Option
For European Option, the holder of the option can exercise his or her right exactly at the expiration date.
For American Option, the holder of the option can exercise his or her right at any time before the option expiration date.

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