Potentiometer Voltage Division Steps:

• Identify the potentiometer as a voltage divider across a power source, say 6V total.
• When slider at end P (one terminal), voltmeter measures voltage from P to reference point, yielding 3V based on polarity.
• When slider at end Q (other terminal), voltmeter measures full or adjusted voltage to reference, yielding 6V.
• Polarity ensures positive readings without reversal.

Why D is correct:

• D (3V at P, 6V at Q) matches standard potentiometer behavior where ends provide partial and full source voltage per Ohm's law division.

Why the others are wrong:

• A: Incorrect; 0V at P implies no voltage drop, violating divider principle.
• B: Duplicate of D but listed separately; not uniquely wrong.
• C: Duplicate of D but listed separately; not uniquely wrong.

Not enough information: Diagram absent, so exact voltages assumed from typical setup.

Final answer: D