The Best Way to Teach Children About Areas of Polygons

The best way to teach children about areas of polygons is to give them:

A) the list of formulas and encourage them to substitute in the values for the variables.
B) diagrams of polygons with number values assigned to the sides, then have them use the formulas to substitute values in for the sides.
C) a calculator to use in conjunction with the formulas .
D) graph paper and have them rearrange parts of polygons to develop the formulas.