Final answer:
In a flowchart simulating a game of picking between two cards, the sentence "What color is the card?" should be placed in a decision box.
Step-by-step explanation:
In a flowchart simulating a game of picking between two cards, the sentence "What color is the card?" should be placed in a decision box. In a flowchart, a decision box is represented by a diamond shape and is used to indicate a decision or a question that has multiple possible outcomes. By placing the sentence in a decision box, Bill can prompt the player to select a color and then branch out to different paths based on that choice.