The expected answers were:
                  
(a)      Multivibrator
A switching circuit which depends on positive feedback for its operation. It is a two-stage amplifier with output of one fedback to the input of the other.
  A relaxation oscillator that generates non-sinusoidal waveforms.
(b) (i)      Astable
      (ii)      Monostable
     (iii)     Bistable
(c)  Two common emitter amplifiers with output of one being fedback to the input of the other and vice versa.                                              
(i)      Astable
-  Has no stable state, it is free running due to its capacitive coupling.
(ii)      Monostable
Monostable can only change when an external trigger pulse is applied.

(iii)     Bistable
-  Has two states and one can change state by application of an external force.

The question was on Multivibrators. As reported, a good number of those who attempted this question gave correct answers to the part (a) but not many could describe the principles of operation desired in part (b).The performance was fairly good.