The length of a rectangular garden exceeds its breadth by $6 \, m$. If the area of the garden is $216 \, m^2$,find the length and the breadth of the garden.

• A
  length $: 10 \, m, \text{ breadth } : 3 \, m$
• B
  length $: 18 \, m, \text{ breadth } : 12 \, m$
• C
  length $: 20 \, m, \text{ breadth } : 13 \, m$
• D
  length $: 24 \, m, \text{ breadth } : 6 \, m$