GMAT Critical Reasoning (CR) | Re: The five specially ordered shipments

Shipping Clerk: The five specially ordered shipments sent out last week were sent out on Thursday. Last week, all of the shipments that were sent out on Friday consisted entirely of building supplies, and the shipping department then closed for the weekend. Four shipments were sent to Truax Construction last week, only three of which consisted of building supplies.
If the shipping clerk’s statements are true, which of the following must also be true?
A. At