Answer:
The projects which maximize Vanguard's shareholder wealth are Project A; Project B; Project D.
Step-by-step explanation:
Projects which maximize the shareholder value are projects delivering Expected Returns which are higher than its risk-adjusted weighted average cost of capital (WACC).
As a result, Project A with Expected return of 15% and risk adjusted WACC of 12%; Project B with Expected return of 12% and risk adjusted WACC of 10%; Project D with Expected return of 9% and risk adjusted WACC of 8%; are the projects that maximize the shareholder's value.
On the other hand, Project C with Expected return of 11% and risk adjusted WACC of 12% is harmful to shareholder value.