What is the classification of the new document stating the exercise will begin 4 May and end on 25 May?

The new document detailing the exercise dates should be classified as Confidential due to its potential implications for national security. While the information contained in the document—specifying the exercise's start and end dates—may not seem sensitive at first glance, it is essential to consider the context in which this information is used.

If the dates pertain to a military exercise or operation, revealing this information could provide insights to potential adversaries about timing, operations, and troop movements, compromising operational security. In the realm of derivative classification, any document that could reasonably be expected to cause damage to national security if disclosed should be classified accordingly.

Confidential is the appropriate classification level because it indicates that the information could cause damage to national security if released. The classifications of Secret and Top Secret indicate a higher degree of sensitivity and potential damage which is not warranted when the sole content revolves around exercise dates without additional sensitive context. Unclassified would not offer the necessary protection, given that operational details should often be guarded to secure the operations being planned.