フリー問題

問題文

In a mobile strategy game, buying a resource pack starts a database lookup of the account, a withdrawal of funds, a log entry and a confirmation mail. The player sees none of those steps. What does the syllabus require for this group of mechanics?

選択肢

1. They must be described as visual requirements, because the effect of the pressed key is obvious to the player.
2. They must be described as formal requirements, because the chain of the started steps is invisible to the player.
3. They must be described as optional requirements, because the value of the bought pack is marginal to the player.
4. They must be described as informal requirements, because the logic of the core loop is known to the player.