Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to measure monitor size [title] Measure the length of the monitor screen. [step] Use a ruler to measure the horizontal length of the monitor from one end to the other. Don't include the frame or structure around the monitor, measure only the viewing screen.

Ending1: [title] Measure the height of the monitor screen. [step] Only measure the image area rather than the frame or border around the monitor. Ending2: [title] Measure the length of the monitor screen from top to bottom. [step] Measure around the screen from top to bottom, starting at the bottom, and moving inward (across the screen). Ending3: [substeps] For example, a 12-inch monitor (100 mm) monitor has 12 inches of screen backing and 16 inches of screen side. A 24-inch monitor (150x 2100 mm) monitor can only have 12 inches of screen backing. Ending4: [substeps] Bring the measuring tape to the base of the monitor. Cup your index and middle fingers around the monitor to measure from the base of the screen.

Answer format: ending1/ending2/ending3/ending4