Answer: When Wood Co. sells the land to a third party.
Explanation: As stated in the question, Wood Co. who purchased the land is a subsidiary of the seller, Power Corp., the parent company. In a consolidated financial statement whereby financial reports of all entities, subsidiaries and all financial attachment of a corporate establishment is accounted for.
Power Corp. owns the entirety of Woods Co. and therefore during a consolidated financial statement reporting, the profit made by Power Corp. from the sale of the land must be recorded when the land is purchased from Woods Co. by a third party.