Suppose that the gain, time constant and dead time of a process with the following transfer function: Gc(s) = 10 exp( - 0.1s)/(0.5s + 1) are known with a possible error of ± 20% of their values. The largest permissible gain Kc of a proportional controller needs to be calculated below taking the values of process gain, time constant and dead time as

• A. 8, 0.6, 0.08
• B. 12, 0.6, 0.12
• C. 8, 0.6, 0.12
• D. 12, 0.4, 0.08