A2. The perimeter of a rectangle, whose sides are whole number centimeters long, is $24 \mathrm{~cm}$. How many centimeters can its sides be?
(A) 12,12
(B) 6,4 or 6,3
(C) 6,6 or 8,4 or 10,2
(D) 8,3
(E) 12,2
A2. The perimeter of the rectangle is $24=2 \cdot(a+b)$, so the sum of the sides $a$ and $b$ is $12 \mathrm{~cm}$. Only in answer (C) is the sum of the sides equal to 12 in all cases.