OFFICIAL EXPLANATIONAttachment:
gre SQUARE.png [ 85.43 KiB | Viewed 21 times ]
The square ABCD having sides 12 unit's each, has diagonal $\(\mathrm{AC}(=\mathrm{BD})\)$ of length $\(12 \sqrt{2}\)$ (Diagonal in a square is $\(\sqrt{2}\)$ times the side).
Same way the diagonal of square PQRS having side 4 unit's each is $\(4 \sqrt{2}(=P R=Q S)\)$
Now, $\(A C-P R=12 \sqrt{2}-4 \sqrt{2}=8 \sqrt{2}\)$ is same as $\(A P+R C=2 R C\)$ (the figure has $\(A P=R C\)$ ), so we get $\(2 R C=8 \sqrt{2} \Rightarrow R C=4 \sqrt{2}\)$
Next the length of the sides of isosceles trapezium QRCB ; is $\(\mathrm{QR}=4, \mathrm{BC}=12 \& \mathrm{RC}=\mathrm{QB}=4 \sqrt{2}\)$
Finally the perimeter of the shaded region i.e. trapezium $\(Q R C B\)$ is $\(Q R+B C+R C+Q B=\)$ $\(4+12+4 \sqrt{2}+4 \sqrt{2}=16+8 \sqrt{2}(=$ Column A quantity $) \&\)$ the area of the shaded portion is $\(\frac{1}{2} \times\)($ Sum of parallel sides $) \(\times\)$ Distance between parallel sides $\(=\frac{1}{2} \times(4+12) \times 4=32(=\)$ column $\(B\)$ quantity)
Clearly $\(16+8 \sqrt{2}<32\)$ i.e. column $B$ has higher quantity when compared with column $\(A\)$.
Hence the answer is (B).