Assertion (A) : Crystal protein Bt toxin does not kill the Bacillus but kills the insects. Reason (R) : Bt toxin exists in inactive form in Bacillus but when ingested by the insect, the acidic pH of its gut changes it into an active form.

Options :

1. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

2. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).

3. Assertion (A) is true, but Reason (R) is false.

4. Assertion (A) is false, but Reason (R) is true.