Problem: a rectangular tank needs to be coated with insulation . the tank has dimensions of 3 feet , 6 feet , and 2 feet . each square foot of insulation costs $ 20 . how much will it cost to cover the surface of the tank with insulation ? 
Options: ['a ) $ 980', 'b ) $ 1060', 'c ) $ 1220', 'd ) $ 1440', 'e ) $ 1650']
d