Student: What is the maximum number of pieces of birthday cake of size 3" by 3" that can be cut from a cake 21" by 21"?
Options:
(A) 5
(B) 7
(C) 49
(D) 20
(E) 25.
Another student: Let's say, hmmm...
The prompt is essentially asking for the maximum number of 3x3 squares that can be cut from a larger 21 by 21 square. Since each 'row' and each 'column' of the larger square can be sub-divided into 7 'pieces' each, we have (7)(7) = 49 total smaller squares (at maximum). Final answer: (C).