Bt toxin is not toxic to human beings because

Question

$\begin{array}{1 1} \text{a. The pro Bt toxin activation requires temperature above human body temperature.} \\ \text{b. Bt toxin recognizes only insect specific targets.} \\ \text{c. The pro Bt toxin activation requires pH lower than that present in human stomach.} \\ \text{d. Conversion of pro toxin to Bt toxin takes place in highly alkaline conditions.} \end{array}$