Correct Answer: Anomaly

Solution : The correct choice is the first option.

Departure from common rule refers to a deviation from the usual or common standard or rule. Anomaly refers to something that deviates from the common rule or norm, making it an appropriate substitute for "departure from common rule".

The meanings of the other options are as follows:

• Quixotic means unrealistic and impractical, often in pursuit of noble ideals.
• Pragmatic means dealing with things sensibly and realistically.
• A stupor is a state of near-unconsciousness or insensibility.

Therefore, the correct answer is anomaly.