As per IS 383 (1970), the grading limit percentage of fine aggregates in Zone II which are passing through a 4.75 mm IS sieve is

Detailed Explanation: IS 383:1970 Fine Aggregate Grading — Zone II at 4.75 mm

IS 383:1970 (Specification for Coarse and Fine Aggregates from Natural Sources for Concrete) classifies fine aggregates into four grading zones (I–IV) based on particle size distribution. Zone I is the coarsest; Zone IV is the finest. Knowing the percentage passing at each standard sieve size is essential for selecting the right sand for a concrete mix.

Why D (90–100%) is correct for Zone II at 4.75 mm:
The 4.75 mm sieve is the upper boundary of fine aggregate by definition. Since fine aggregate must pass 4.75 mm (otherwise it is classified as coarse aggregate), virtually 100% of any fine aggregate must pass this sieve — with a small allowance of 0–10% retained for oversize particles mixed in naturally. Across all four zones, the percentage passing 4.75 mm ranges from 90–100% (Zones I, II, III) to 95–100% (Zone IV). Answer D correctly represents this for Zone II.

IS 383:1970 Grading Limits — % Passing (All Zones)

IS Sieve	Zone I (Coarsest)	Zone II	Zone III	Zone IV (Finest)
10 mm	100	100	100	100
4.75 mm	90–100	90–100	90–100	95–100
2.36 mm	60–95	75–100	85–100	95–100
1.18 mm	30–70	55–90	75–100	90–100
600 μm	15–34	35–59	60–79	80–100
300 μm	5–20	8–30	12–40	15–50
150 μm	0–10	0–10	0–10	0–15

Key Concepts for Students

• 4.75 mm is the boundary between coarse and fine aggregate — so ~90–100% of fine aggregate must pass this sieve in all zones.
• The options given (35–59%, 0–10%, 15–34%) correspond to Zone II limits at the 600 μm, 150 μm, and 300 μm sieves respectively — not the 4.75 mm sieve.
• Zone II sand is the most widely used for reinforced concrete. IS 456 generally recommends Zones II and III for structural concrete.
• Memorise the 600 μm column as a checkpoint: 15–34% (Zone I) → 35–59% (Zone II) → 60–79% (Zone III) → 80–100% (Zone IV). The zones increase in fine content.