A practical $$R$$-$$C$$ sinusoidal oscillator is built using a positive feedback amplifier with a closed loop gain slightly less than unity.

Given figure shows a two stage small signal transistor feedback amplifier. Match the defective component (listed on the left hand side below) with its probable effect on the circuit (listed below)

List - $${\rm I}$$
$$A.$$ Capacitor $${C_1}$$ is open
$$B.$$ Capacitor $${C_3}$$ is open
$$C.$$ Capacitor $${C_4}$$ is open
$$D.$$ $$R{C_2}$$ is shorted

List - $${\rm II}$$
$$P.$$ All $$dc$$ voltages normal, $${V_0}$$ increases marginally
$$Q.$$ Collector of $$T{R_2}$$ at $${V_{cc}},\,\,{V_0} = 0$$
$$R.$$ All $$dc$$ voltages normal, gain of $${2^{nd}}$$ stage decreases, $${V_0}$$ decreases.
$$S.$$ All $$dc$$ voltage normal, $${V_0} = 0$$
$$T.$$ All $$dc$$ voltages normal, overall gain of the amplifier increases, $${V_0}$$ increase
$$U.$$ No change

A Wein bridge oscillator is shown in figure. Which of the following statements are true if $$'f'$$ is the frequency of oscillation?

In a common Emitter amplifier, the un bypassed emitter resistance provides