Semantics of memory properties of a computed array?

This is an application that allows users to mark things. Tags are just strings.

The array of objects TagHoldercontains a list of all the tags used in the application, with a Boolean message, if a tag is selected, but this is an implementation detail.

The external interface calls two methods: selectedTagsand setSelectedTags:, which return and accept arrays of strings.

I would like these two methods to work as accessors for the declared property selectedTags.

Now, my question is:

What was the correct memory management semantics for the declaration for this property?

The sample code that I have in mind is this (the code is not tested, so please bear typos):

@interface TagInfo : NSObject
@property (strong, nonatomic) NSString *tag;
@property (nonatomic) BOOL selected;
@end


@interface SomeClass : NSObject
@property (memorytype, nonatomic) NSArray *selectedTags;
@end

@implementation TagHolder

- (NSArray *)selectedTags
{
    // tagInfoArray is an array of all TagInfo objects
    NSPredicate *selPred = [NSPredicate predicateWithFormat: @"selected == YES"];
    NSArray *selectedTagInfoObjects = [[self tagInfoArray] filteredArrayUsingPredicate: selPred];

    NSArray *selectedTags = [selectedTagInfoObjects valueForKey: @"tag"];
    return selectedTags;
}

- (void)setSelectedTags: (NSArray *)selectedTags
{
    for (TagInfo *tagInfo in [self tagInfoArray]) {
        tagInfo.selected = [selectedTags containsObject: tagInfo.tag];
    }
}

@end

memorytype? , , , assign, copy unsafe_unretained, ?

ARC, , .