Which of the following can be a status of a complex instrument?

In the context of complex instruments, the status labeled as "Book" indicates that the positions or trades have been recorded in the trading system. This status is crucial as it signifies that the complex instrument is officially recognized and accounted for within the trader's or firm's portfolio. It demonstrates that the trade has successfully moved past the initial stages and is now part of the trader’s financial standing.

The term "Book" is used in trading environments to refer to the overall collection of trades or positions held by a trader or trading desk. It reflects a state of readiness for further actions like management, analysis, or reporting.

Other statuses typically used in trading, such as "Executed," refer to trades that have been completed successfully, while "Temporary" may indicate an intermediate status that is not definitive. "Invalid" would suggest that a trade or position cannot be processed or recorded for some reason. However, the status 'Book' is what ultimately confirms that the complex instrument is officially recognized in the financial records.