Answer:
31 March 2021
Explanation:
The contract should be recorded on 31 March 2021 because according to the US Generally Accepted Accounting Principles, revenue should be recognize in the book only when service has been rendered to the customer, the selling price of product is fixed and confirmation of service arrangement and amount to be collected.
With regards to the above scenario, since the equipment was not delivered until 31 March, then 31 of March will be recognized.