Estate Finance Family Tax Plan Question

On January 2, 1990, Hank Brady establishes the Judge Hank Brady Irrevocable Dynasty Trust with Tenleytown Trust Company as trustee. On January 10, 1990, Hank transfers 100 shares of Brady, Inc. stock to the trust worth $1 million. Hank Brady does not allocate any GST exemption to the trust either during the transfer or at any point after, and, therefore, the trust has an inclusion ratio of 1. The trustee has the discretion to distribute principal to the grantor's son, Mike, and Mike's sons, Greg, Peter and Bobby to provide for their welfare. Upon Mike's death, the remainder is distributed in equal shares to Mike's sons. On January 10, 2020, Mike dies. On January 10, 2020, the fair market value of the trust is $10 million. How much GST tax does the trust or its beneficiaries owe in 2020 and why? Who is responsible for paying the tax?