in a grillage footing the beams in each tier are spaced such that the minimum spacing between the flanges of the two consecutive beams is not less than;

Correct option is B

Grillage footing is a special foundation used to spread heavy column loads over a larger area.
It is made of steel beams arranged in layers (tiers), with each tier placed at right angles to the one below.
Proper spacing between beams in each tier is essential for:
Effective load distribution
Avoiding overlapping or structural interference
As per standard practice, the minimum clear spacing between the flanges of adjacent beams should be at least 75 mm.