List of top Instrumentation and Process Control Questions on Analysis of closed loop systems including stability

Liquid flowing through a heat exchanger (HX) is heated. A bypass stream is provided to control the temperature of the heated exit stream. From the given plumbing options, the one that provides the most effective temperature control for large disturbances while avoiding vaporization in the heat exchanger is 

In the block diagram shown in the figure, the transfer function $G=\dfrac{K}{(\tau s+1)}$ with $K>0$ and $\tau>0$. The maximum value of $K$ below which the system remains stable is \(\underline{\hspace{2cm}}\) (rounded off to two decimal places).

It is required to control the volume of the contents in the jacketed reactor shown in the figure. 
 

Which one of the following schemes can be used for feedback control?