给词语排序，并写出理由。

1．博士生  小学生  大学生  硕士生  中学生

     排序：                                                                                                 

     理由：                                                                                                 

2．儿子  曾祖父  父亲  祖父

     排序：                                                                                                 

     理由：                                                                                                 

3．国庆节  儿童节  劳动节  建军节  植树节

     排序：                                                                                                 

     理由：                                                                                                 

4．西安  中国  东亚  陕西  亚洲

     排序：                                                                                                 

     理由：                                                                                                

患者，男，55岁。间断肉眼血尿半年，近期耻骨上方疼痛。MR检查示膀胱壁增厚，膀胱底部可见一大小约3.2cm×2.5cm×3.8cm的菜花状异常信号影，在T₁WI上与膀胱壁等信号，高于尿液信号，但低于膀胱周围脂肪信号，T₂WI呈中等信号，高于膀胱壁信号。增强扫描病变及增厚的膀胱壁明显不均匀强化。

该例最可能的诊断是（）

A.膀胱息肉

B.膀胱移行细胞癌

C.膀胱内血凝块

D.膀胱炎局部肉芽组织形成

E.膀胱结石