Please help me gain a better understanding of this matter

use gurufocus.com and thatswacc.com to find the weighted average cost ofcapital for Dunkin' Brands Group, Inc. (DNKN).

a)Explain how the WACC is calculated.

b)Explain the difference in the WACC as calculated on the two websites.

c)Explain the WACC in the context of a hurdle rate, return on invested capital (ROIC), an optimal capital structure, an optimal capital budget, and the golden rule of value creation.