...
def question(message):
keyboard = types.InlineKeyboardMarkup(row_width=2)
a = types.InlineKeyboardButton(text="Ответ", callback_data="get_answer")
keyboard.add(a)
bot.send_message(chat_id, "Вопрос", reply_markup = keyboard)
@bot.callback_query_handler(func=lambda call: call.data == 'get_answer') #call: call.data == 'some_data'
def callback_get_answer(call):
if call.message:
bot.send_message(chat_id, "Ответ", reply_markup = "")