Final answer:
A wardrobe and a nightstand are two examples of furniture that utilize vertical lines, characterized by their up-and-down orientation which can be seen in their overall tall and narrow designs.
Step-by-step explanation:
Two pieces of furniture that utilize a vertical line are a C) Wardrobe and a B) Nightstand. Vertical lines are lines that run up and down, as opposed to horizontal lines that run side to side. A wardrobe, which is tall and narrow, emphasizes verticality through its design, often reaching from floor to ceiling and featuring doors that emphasize its height. A nightstand, although not as tall as a wardrobe, also frequently features vertical lines in its structure, through its legs, sides, and the overall rectangular shape that stretches upwards more so than outwards. An example for reference could be Figure 3.3.2: Chest of drawers (CA 1730, veneered with gilt-bronze mounts and marble top, 91.1 x 158.1 x 66.0 cm), which although not specifically mentioned in the options, shares similarities with a nightstand in terms of design features that illustrate the use of vertical lines.