$7.$ D creates a trust with an independent trustee, giving the trustee the power to give income to A or B for D$\text{'}$s life, with a remainder to C or C$\text{'}$s estate. A$,$ B$.$ and C are unrelated to D$.$

b$.$ What is the result if$,$ in addition, D provides that the independent trustee must give income necessary for D$\text{'}$s support and maintenance to D with any excess income in any year to go to A and B$?$