Which text accurately represents an algorithm?

The choice that accurately represents an algorithm is the instruction that involves a conditional statement: "Shake bulb; if it rattles, replace it." This statement outlines a clear process that includes a specific action to take (shaking the bulb) followed by a decision point (if it rattles) that determines the next step (replace it).

Algorithms are typically characterized by being precise, having a defined number of steps, and offering a way to handle different situations based on specific conditions. In this case, the process involves both an action and a conditional outcome that guides the decision-making process, which is a fundamental aspect of algorithms.

Other options lack the structured decision-making component that defines an algorithm. For instance, "Insert key, turn key, open door" describes a sequence of actions but does not involve any conditions that alter the steps based on the outcome. Similarly, "Put the cat in the bag" and "Make a cake" are vague and do not provide a clear step-by-step procedure or choice based on conditions.