Final answer:
Just before Henderson Laboratories opened for business, it was most likely under construction, preparing the physical location for operations.
Step-by-step explanation:
The most likely state or condition of Henderson Laboratories just before it opened for business is D) Under construction. Generally, before a business begins operations, there is a period where the physical location is being prepared. This can include constructing the building, setting up the interior, and getting all the necessary equipment and furnishings in place. If we consider the scenario provided, where a construction worker is laid off and takes a temporary job at a fast food restaurant, it indicates that the construction phase might have just been completed or is near completion, leading to less need for labor in that sector.