Topic: Idioms & Phrases,

Best Answer Explained in Below-:

The phrase "at sixes and sevens" is an idiomatic expression that refers to a state of confusion, disorder, or disarray. When applied to the context of "All the furniture in the room were--," it implies that the furniture is arranged haphazardly or chaotically.

The other options do not appropriately convey a sense of disorder related to the physical arrangement of items. "At random" suggests a lack of order but does not specifically hint at confusion; instead, it refers more to the arbitrary selection or arrangement. "Apple of discord" refers to a source of disagreement or conflict, and thus is not directly related to furniture or physical arrangement. "At a loss" indicates confusion in decision-making or understanding but doesn’t apply to a physical arrangement or state of objects.

Therefore, "at sixes and sevens" is the most fitting choice as it captures the sense of disarray specifically associated with the arrangement of furniture in a room, illustrating a clear image of chaos and disorder.