The differential equation $$\frac{{{\text{dx}}}}{{{\text{dt}}}} = \left[ {\frac{{1 - {\text{x}}}}{\tau }} \right]$$   is discretised using Euler's numerical integration method with a time step ΔT > 0. What is the maximum permissible value of ΔT to ensure stability of the solution of the corresponding discrete time equation?

A. 1

B. $$\frac{\tau }{2}$$

C. $$\tau $$

D. $$2\tau $$

Answer: Option D