下列哪项实现的功能是打电话到10086 （ ）？
[[UIApplicationsharedApplication]openURL:[NSURLURLWithString:@"tel://10086"]];
[[UIApplicationsharedApplication]openURL:[NSURLURLWithString:@"tel:10086"]];
[[UIApplicationsharedApplication]openURL:[NSURLURLWithString:@"tel 10086"]];
[[UIApplicationsharedApplication]openURL:[NSURLURLWithString:@"tel:\\10086"]];
