Company A signed a sales contract with a foreign buyerfor exporting Tea Sets, under FOB term. At the buyer’s request, the seller agreedto charter a vessel at buyer’s account. When the date of shipment became due,the seller was still unable to get a vessel for shipment. The buyernot only disagreed to modify the date of shipment, but also cancelled thecontract and claimed for loss, because the seller failed to effect shipmentwithin the time stipulated in the contract. Question: Is the seller responsible forfailure to effect shipment for his inability to charter a ship?(是/否) ( )