The correct option is C 32
Let the side of big cube be 4cm. So, one side of smaller cube =1cm
n=sideofbigcubesideofsmallcube=41=4.
Number of smaller cubes having at least one surface painted with green xolour = Number of smaller cubes at 8 corners + Number of smaller cubes at 8 edges + Number of smaller cubes at 2 surfaces
=8+(n−2)×8+(n−2)2×2=8+16+8=32