How does the protein produced by $Bt$ affect insects?

• A
  It inhibits the synthesis of $DNA$ in the insect's gut.
• B
  It binds to the surface of midgut epithelial cells and creates pores,causing cell swelling and lysis.
• C
  It acts as a neurotoxin that paralyzes the insect's nervous system.
• D
  It prevents the insect from digesting food by blocking digestive enzymes.