When asked about their opinion about the president, many citizens would prefer to see him step aside ___________ younger men.[ ]

A. in need of        

B. in terms of      

C. in praise of        

D. in favour of

在某种牛中，基因型为AA的个体的体色是红褐色，aa是红色。基因型为Aa的个体中雄牛是红褐色的，而雌牛是红色的。一头红褐色母牛生了一头红色小牛，这头小牛的性别及基因型为（）

A.雄性或雌性，aa

B.雄性，aa或Aa

C.雄性，Aa

D.雌性，Aa