Step 1: Concept
Packing efficiency of FCC $= 74% = 0.74$.
Total volume of all particles in unit cell $= 0.74 \times \text{Volume of unit cell}$.
Step 2: Total particle volume
Total Volume $= 0.74 \times 1.6 \times 10^{-23} = 1.184 \times 10^{-23} \text{ cm}^3$.
Step 3: Volume of one particle
In FCC, number of atoms per unit cell $(Z) = 4$.
Volume of one particle $= \frac{1.184 \times 10^{-23}}{4} = 0.296 \times 10^{-23} = 2.96 \times 10^{-24} \text{ cm}^3$.
Final Answer: (B)