单选题

阅读下面代码： @interface Parent : NSObject...

Question

阅读下面代码：

@interface Parent : NSObject
@property(nonatomic,assign)int age
@end
@implementation Parent
@dynamic age
@end
@interface Child : Parent
@end
@implementation Child
@synthesize age = _age
@end

请问以下代码的输出是：（）

Parent *parent = [Parent new]
parent.age = 30
NSLog(@"parent age: %d", parent.age)
Child *child = [Child new]
child.age = 8
NSLog(@"child age: %d", child.age)

A.

 编译不通过

B.

编译能通过，运行时crash

C.

parent age:30child age:8

D.

 parent age:30child age:30