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: abcd is a square . e and f are the midpoints of sides cd and bc , respectively . what is the ratio of the shaded region area to the unshaded region ? 
Options: ['a ) 1 : 1', 'b ) 2 : 1', 'c ) 3 : 1', 'd ) 5 : 3', 'e ) 8 : 3']
d

Problem: the sides of a square region , measured to the nearest centimeter , are 7 centimeters long . the least possible value of the actual area of the square region is 
Options: ['a ) 42.25 sq cm', 'b ) 45.25 sq cm', 'c ) 43.25 sq cm', 'd ) 50.25 sq cm', 'e ) 52.25 sq cm']
a

Problem: can c and can в are both right circular cylinders . the radius of can c is twice the radius of can b , while the height of can c is half the height of can b . if it costs $ 4.00 to fill half of can b with a certain brand of gasoline , how much would it cost to completely fill can c with the same brand of gasoline ? 
Options: a ) $ 1 , b ) $ 2 , c ) $ 4 , d ) $ 8 , e ) $ 16

e