What phrase indicates the requirement to study for passing a test?

The phrase "in order to" is used to express purpose or intention. When applied to the context of studying for passing a test, it clearly conveys that studying is necessary to achieve that specific goal. It implies a direct connection between taking action (studying) and the desired outcome (passing the test). This phrase is often utilized to indicate that an effort or action is undertaken for achieving a particular result, which in this case is passing the test.

Other phrases, such as "in case of," do not suggest an action taken for a specific reason but rather imply a conditional situation. "For the sake of" conveys a motivation or reason but doesn't specifically indicate an action being tied to a goal. "To the point of" suggests reaching a certain level or degree, but it doesn't focus on the purposeful action necessary to achieve a result. Hence, "in order to" is the most appropriate choice for indicating the requirement to study for passing a test.