b. which functional area controls the amplitude?\na input\nb display\nc vertical\nd horizontal

b. which functional area controls the amplitude?\na input\nb display\nc vertical\nd horizontal
Answer
Brief Explanations:
In an oscilloscope or similar equipment, the vertical - axis controls the amplitude of the signal being displayed. The input is where the signal enters, the display is for showing the signal, and the horizontal controls time - related aspects.
Answer:
C. Vertical