In which of the following abdominal segments is the mushroom gland present in a cockroach?

• A
  $6^{\text{th}}-7^{\text{th}}$
• B
  $8^{\text{th}}-9^{\text{th}}$
• C
  $5^{\text{th}}-6^{\text{th}}$
• D
  $9^{\text{th}}-10^{\text{th}}$