Selecting instrument for precise length measurement

Steps:

• Identify requirements: 10 cm length needing 0.1 cm (1 mm) precision.
• Recall instrument capabilities: range and smallest readable division.
• Compare: metre rule and tape offer ~1 mm precision but lower accuracy for short distances; micrometer excels in precision but limited to small openings; vernier calipers suit both range and precision.
• Select vernier calipers as optimal match.

Why D is correct:

• Vernier calipers measure external lengths up to 10-30 cm with 0.1 mm (0.01 cm) precision via sliding scale principle, meeting and exceeding 0.1 cm requirement.

Why the others are wrong:

• A. Metre rule: Typically marked in 1 mm intervals but prone to parallax error, limiting reliable precision to >0.1 cm for short distances.
• B. Micrometer: Provides 0.01 mm precision but maximum jaw opening ~2-3 cm, unsuitable for 10 cm length.
• C. Tape measure: Designed for longer distances with ~1-5 mm markings, lacking stability for precise 0.1 cm readings on small scales.

Final answer: D