In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: how many 4 x 5 x 8 cubes could fit in a 10 x 16 x 84 box ? 
Options: a ) 84 , b ) 90 , c ) 85 , d ) 77 , e ) 64
a

Problem: the perimeter of one face of a cube is 20 cm . its volume will be : 
Options: a ) 125 cm 3 , b ) 400 cm 3 , c ) 250 cm 3 , d ) 625 cm 3 , e ) none of these
a

Problem: the slant height of a cone is 13 cm and radius of the base is 9 cm , find the curved surface of the cone ? 
Options: a ) 367 , b ) 378 , c ) 365 , d ) 26 , e ) 28

a