JSON is not recognizing accents nor question marks in ios - ios

Question

I'been trying to parse JSON data retrieved from my server, but when the server sends JSON with accents or question marks, it shows as null values.
It would be great if someone could help me solve this issue.
Here is my code
- (void)viewDidLoad
{
[super viewDidLoad];
NSString *urls=[NSString stringWithFormat:#"http://myserver.myserver/myserver"];
NSLog(#"%#",urls);
NSURL *url =[NSURL URLWithString:urls];
NSData* data = [NSData dataWithContentsOfURL:url];
//fetch the data to the JSON Foundation opject.
[self performSelectorOnMainThread:#selector(fetchedData:)
withObject:data waitUntilDone:YES];
}
- (void)fetchedData:(NSData *)responseData {
//parse out the json data
NSError* error;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
//process the JSON Foundation object to the view.
[self processData:json];
}
-(void)processData:(NSDictionary *) JSONObject{
NSString *kl = [JSONObject valueForKey:#"qlk"];
NSString *an= [JSONObject valueForKey:#"alk"];
NSString *bn = [JSONObject valueForKey:#"blk"];
NSString *cn =[JSONObject valueForKey:#"clk"];
NSString *dn =[JSONObject valueForKey:#"dlk"];
NSString *correcta =[JSONObject valueForKey:#"rlk"];
qkl.text=pregunta;
akl.text =an;
bkl.text =bn;
ckl.text=cn;
dkl.text=dn;
}
And the JSON
{ "qlk": "¿De qué color es el caballo blanco de Simon Bolivar?", "alk": "Negro", "blk": "Cafe", "clk": "Blanco", "dlk": "Rojo", "rlk": "c" }
Thanks.