An estate freeze is suitable only if Cynthia can live on the fixed economic interest she retains. The freeze typically converts her growth interest into fixed-value preferred shares and transfers future growth to children, a trust, or other successors. That structure is poor planning if she still needs flexible access to future growth for lifestyle, health-care costs, or retirement security. The children's higher marginal tax rates would not support a freeze for income-splitting purposes. Hyperinflation actually increases the risk that a fixed income stream becomes inadequate. A need for flexibility in changing beneficiaries may point away from a rigid freeze unless a trust is carefully designed. The answer is therefore D: Cynthia's ability to live on a fixed stream of income is the factor that makes the freeze viable. Study Guide focus: estate-freeze suitability, retained preferred shares, income sufficiency, growth transfer, and estate planning risk. The planner should stress-test retirement income, health costs, and inflation before concluding that the freeze is affordable.

===============