How do I insert string to sqlite in Objective-C?

I could not insert NSMutableString to sqlite. I get the information successfully from web server and create the sqlite file successfully but I could not insert the data from web to sqlite.

I think the problem is here.

NSString *insertSQL = @"INSERT INTO Questions VALUES (result)";

but I am not sure and I could not solve this problem. Could anyone help me please?

- (void)getInforamtionFromWeb {
    NSURL *url = [NSURL URLWithString:kGetUrl];
    data = [NSData dataWithContentsOfURL:url];
    NSError *error;
    json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
    result = [[NSMutableString alloc] init];
    for (NSObject * obj in json)
    {
        [result appendString:[obj description]];
    }
}

-(void)initiatSqlite{
    // Get the documents directory
    dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    docsDir = dirPaths[0];
    // Build the path to the database file
    _databasePath = [[NSString alloc]
                     initWithString: [docsDir stringByAppendingPathComponent:
                                      @"Questions.db"]];
    NSFileManager *filemgr = [NSFileManager defaultManager];
    if ([filemgr fileExistsAtPath: _databasePath ] == NO)
    {
        const char *dbpath = [_databasePath UTF8String];
        if (sqlite3_open(dbpath, &_contactDB) == SQLITE_OK)
        {
            char *errMsg;
            const char *sql_stmt =
            "CREATE TABLE IF NOT EXISTS Questions (ID INTEGER PRIMARY KEY AUTOINCREMENT, Question Text, AnswerA Text, AnswerB Text, AnswerC Text, AnswerD Text, CorrectAnswer Text, Explanation Text)";
            if (sqlite3_exec(_contactDB, sql_stmt, NULL, NULL, &errMsg) != SQLITE_OK)
            {
                [self Worningtitle:@"Error" Message:@"Failed to create table"];
            }
            sqlite3_close(_contactDB);
        } else {
            [self Worningtitle:@"Error" Message:@"Failed to open/create database"];

        }
    }

}
- (void) insertData
{
    sqlite3_stmt    *statement;
    const char *dbpath = [_databasePath UTF8String];


    if (sqlite3_open(dbpath, &_contactDB) == SQLITE_OK)
    {
        NSString *insertSQL = @"INSERT INTO Questions VALUES (result)";

        const char *insert_stmt = [insertSQL UTF8String];
        NSLog(@"%s",insert_stmt);
        sqlite3_prepare_v2(_contactDB, insert_stmt, -1, &statement, NULL);
        sqlite3_bind_text(statement, 1, [result UTF8String], -1, SQLITE_TRANSIENT);

        if (sqlite3_step(statement) == SQLITE_DONE)
        {
            NSLog(@"Product added");
        } else {
            NSLog(@"Failed to add Product");
        }

        sqlite3_finalize(statement);
        sqlite3_close(_contactDB);
    }
}