Given the task definition and input, reply with output. In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: a farmer wishes to start a 100 square metres rectangular vegetable garden . since he has only 30 m barbed wire , he fences three sides of the garden letting his house compound wall act as the fourth side fencing . the dimension of the garden is : 
Options: ['a ) 15 m × 6.67 m', 'b ) 20 m × 5 m', 'c ) 30 m × 3.33 m', 'd ) 40 m × 2.5 m', 'e ) none of these']

b