The top face of the cube has area = 7 × 7 = 49 cm².
Each depression has diameter = 2 × 0.35 = 0.70 cm, so each occupies a square of side 0.70 cm.
Number of depressions = $\dfrac{49}{0.70 \times 0.70} = \dfrac{49}{0.49} = 100$
Answer: (b) 100
Each hemispherical depression occupies a circular area of diameter 0.70 cm. For packing purposes, treat each as fitting in a 0.70 cm × 0.70 cm square on the face. Divide total face area (49 cm²) by area per depression (0.49 cm²) to get the maximum count of 100. This is a straightforward area-division problem linked to Chapter 12 concepts of combining/removing solids.