Step 1: Recall the standard values.
FCC packs at about 74 percent, BCC at about 68 percent, and simple cubic at about 52 percent.
Step 2: Check simple cubic.
In a simple cubic cell there is 1 atom and the edge is $a = 2r$. The efficiency is
\[ \frac{\frac{4}{3}\pi r^3}{(2r)^3}\times 100 = \frac{\pi}{6}\times 100 \approx 52.36\% \]
Step 3: Match.
The value 52.36 percent belongs to simple cubic.
\[ \boxed{\text{Simple cubic, option 4}} \]