In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
One example: Problem: if the sides of a triangle are 20 cm , 12 cm and 16 cm , what is its area ? 
Options: a ) 70 , b ) 79 , c ) 85 , d ) 96 , e ) 92
Solution is here: d
Explanation: "Based on the pythagorean theorem, the triangle with sides 20 cm, 12 cm and 16 cm is right angled, where the hypotenuse is 20 cm. area of the triangle = 1 / 2 * 12 * 16 = 96 cm 2 answer : option d"

Now, solve this: Problem: if the length of the diagonal of a square is 20 cm , then its perimeter must be 
Options: ['a ) 40', 'b ) 38', 'c ) 27', 'd ) 29', 'e ) 11']
Solution:
a