Problem: consider a right circular cone of base radius 4 and height 10 cm . a cylinder is to be placed inside the cone with one of the flat surface resting on the base of the cone . find the largest possible total surface area ( in sq cm ) of the cylinder . 
Options: ['a ) 100 π / 3', 'b ) 80 π / 3', 'c ) 120 π / 7', 'd ) 130 π / 9', 'e ) 110 π / 7']
a