Bacillus thuringiensis produces proteins (Bt toxin) that kill certain insects. Identify the correct statements.
(A) Bt toxin protein exists as an inactive form (protoxin) in Bacillus thuringiensis.
(B) Bt toxin protein exists as an active form toxin in the insect gut.
(C) The alkaline pH of the gut of an insect solubilize the toxin and converts in an inactive form.
(D) The toxin is coded by a gene crylAc named cry.
Choose the correct answer from the options given below:

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.