Problem: a water tank , having the shape of a rectangular prism of base 100 square centimeters , is being filled at the rate of 1 liter per minute . find the rate at which the height of the water in the water tank increases . express your answer in centimeters per minute . 
Options: ['a ) 30 cm', 'b ) 10 cm', 'c ) 50 cm', 'd ) 90 cm', 'e ) 70 cm']
b