$$D$$是等腰锐角三角形$$ABC$$的底边$$BC$$上的一点，则$$AD$$，$$BD$$，$$CD$$ 满足关系式．
选项为:A:$$A{{D}^{2}}=B{{D}^{2}}+C{{D}^{2}}$$  B:$$A{{D}^{2}}\textgreater B{{D}^{2}}+C{{D}^{2}}$$  C:$$2A{{D}^{2}}=B{{D}^{2}}+C{{D}^{2}}$$  D:$$2A{{D}^{2}}\textgreater B{{D}^{2}}+C{{D}^{2}}$$  请回答其中一个选项.