Q:

Error CS0234 The type or namespace name 'SendTextMessageAsync' does not exist in the namespace 'Telegram.Bot'

I want to create InlineKeyBord in telegram bot in c# 
but I have this error:

CS0234 The type or namespace name 'SendTextMessageAsync' does not exist in the namespace 'Telegram.Bot' 

var keyboard = new ReplyKeyboardMarkup(new [] {
  new [] // 1st row
  {
    new KeyboardButton("1"),
      new KeyboardButton("2"),
  },
  new [] // 2nd row
  {
    new KeyboardButton("3"),
      new KeyboardButton("4"),
  }
});

await Telegram.Bot.SendTextMessageAsync(message.Chat.Id, "Choose", replyMarkup: keyboard);

A:

Change:
await Telegram.Bot.SendTextMessageAsync(message.Chat.Id, "Choose", replyMarkup: keyboard);

to:
// see https://mrroundrobin.github.io/telegram.bot/html/M_Telegram_Bot_TelegramBotClient__ctor.htm
var bot = new Telegram.Bot.TelegramBotClient(yourtokenhere); 
await bot.SendTextMessageAsync(message.Chat.Id, "Choose", replyMarkup: keyboard); 

