Comparing metric prefixes for length units

Steps:

• Identify prefixes: T (tera) = 10^12, G (giga) = 10^9, μ (micro) = 10^-6, p (pico) = 10^-12.
• Rank sizes: Tm (10^12 m) > Gm (10^9 m) > μm (10^-6 m) > pm (10^-12 m).
• Largest unit: Tm at 10^12 meters.
• Smallest unit: pm at 10^-12 meters.

Why D is correct:

• Tm represents 10^12 meters (largest scale), pm represents 10^-12 meters (smallest scale) per SI prefix definitions.

Why the others are wrong:

• A: Gm (10^9 m) is not the largest; Tm exceeds it.
• B: No valid pair provided.
• C: μm (10^-6 m) is not the smallest; pm is far smaller.

Final answer: D