Two years ago, Herbert, a widower, made a gift of marketable securities to his 35-year-old daughter, Sabrina, on which he paid a federal gift tax of $3 million. When Herbert died in 2016,his estate had been greatly reduced in value due to his having given away most of his assets over his lifetime. Herbert's executor filed an estate tax return showing an estate tax liability attributable to the gift to Sabrina. The estate tax was not paid because the estate had no liquid assets. The IRS assesses the portion of the estate tax related to this gift that Sabrina previously received against Sabrina under the rules relating to transferee liability. Is Sabrina liable for the estate tax?