Final answer:
The game will have one million users in the near future.
Step-by-step explanation:
The k-factor in this question refers to the growth rate of the game's user base. When the k-factor is one, it means that each existing user brings in one new user. Since there are one million users initially, and each brings in one new user, the user base will stay at one million. Therefore, the answer is b. One million.