What is component 9 in figure T-2?

In standard electronic schematics, a jagged zigzag line represents a resistor. When an arrow points diagonally through it or rests against it, it signifies that the component's resistance is adjustable. Therefore, component 9 in Figure T-2 is a variable resistor. The other options are incorrect based on their standard symbols. A variable capacitor is drawn as two parallel flat lines with an arrow through them. A variable inductor is drawn as a coiled line with an arrow, and a variable transformer consists of two separate coils sharing a core line with an arrow.