There are four birds ______ the tree. And there're many oranges ____ it, too. [ ]

A. in, in

B. in, on

C. on, in

D. on, on

生育年龄已婚妇女，平时月经周期规则，一旦月经过期______天或以上，应疑为妊娠；若停经已达______周，妊娠可能性更大。