Correct Answer:
Option C - As per IS 456 : 2000 Cl 5.3.3.1 for heavily reinforced members as in the case of ribs of main beams, the nominal maximum size of aggregate should usually be restricted to 5 mm less than the minimum clear distance between the main bars or 5 mm less than the minimum cover to the reinforcement whichever is smaller.
C. As per IS 456 : 2000 Cl 5.3.3.1 for heavily reinforced members as in the case of ribs of main beams, the nominal maximum size of aggregate should usually be restricted to 5 mm less than the minimum clear distance between the main bars or 5 mm less than the minimum cover to the reinforcement whichever is smaller.