The sixth property
@property (nonatomic, copy) NSString* disability
has a synthesis directive as @synthesize disability=_disability. It will be synthesized exactly as we saw the synthesis of the first property, except that we tell the compiler to associate the disability property with the _disability instance variable.
A possible synthesis of this property is as follows:
-(NSString*) disability{ return _disability;
}
-(void) setDisability:(NSString*)newDisability{ if(_disability != newDisability){
    [_disability release];
_disability = [newDisability copy]; }
}