Comcorp Shipping Clerk: Last week, no shipments of building supplies were sent out on Friday. The five specially ordered shipments sent out last week were sent out on Thursday, and each of those specially ordered shipments consisted entirely of building supplies. Four shipments were sent to Truax Construction last week, none of which consisted of building supplies.
If the shipping clerk's statements are true, which of the following must also be true? There were 5 specially ordered shipments last week, all sent on Thursday, and each one consisted entirely of building supplies. Also, 4 shipments were sent to Truax Construction, and none of those consisted entirely of building supplies. And no shipments consisting entirely of building supplies were sent on Friday.
(A) All of Comcorp's shipments of building supplies last week were specially ordered.
Not must be true. There could have been a regular shipment consisting entirely of building supplies that was not specially ordered.
(B) None of Comcorp's shipments sent on friday of last week was sent to Truax Construction.
Not must be true. Truax shipments are not entirely building supplies, so they still could have been sent on Friday.
(C) None of the shipments sent by Comcorp to Truax Construction last week was specially ordered.
This must be true.
Every specially ordered shipment consisted entirely of building supplies, but
none of the Truax shipments consisted entirely of building supplies, so no Truax shipment could be specially ordered.
(D) None of Comcorp's shipments sent on Thursday of last week was sent to Truax Construction.
Not must be true. Truax could have received shipments on Thursday, as long as those shipments were not entirely building supplies.
(E) All of Comcorp's shipments of building supplies last week were sent out on Thursday.
Not must be true. A shipment consisting entirely of building supplies could have been sent on a day other than Thursday, as long as it was not Friday.
Answer: (C)