Problem: a pyramid has a square base of 6 cm , and the four lateral faces are four congruent equilateral triangles . what is the total surface area of the pyramid in square cm ? 
Options: ['a ) 36 + 18 * sqrt ( 3 )', 'b ) 36 + 36 * sqrt ( 3 )', 'c ) 72', 'd ) 72 + 36 * sqrt ( 3 )', 'e ) 72 + 72 * sqrt ( 3 )']
b