Laura, a widow, has two adult children Brian and Sarah. Brian is well settled financially but Sarah struggles with managing her finances due to a spendthrift lifestyle. Laura also has a younger sister Janet who has a disability and qualifies for the disability tax credit. Laura is considering establishing a testamentary trust through her will for the benefit of her children and her sister. her estate is worth $500,000 with diverse investment expected to generate about 7% return annually. which of the following options could be the most tax efficient way to structure the testamentary trusts? A) Create a single testamentary trust with both Brian and Sarah as beneficiaries, subject to the top tax rate of 33% on all income. B) Create two separate testamentary trust one for Brian and one for Sarah in order to take advantage of income splitting. C) Leave the entire estate to Brian, trusting him to distribute assets and income fairly among Sarah and Janet. D) Create a qualified disability trust for Janet and a separate trust for her children to distribute the income at lower tax rates