If R_{T}, R_{h} represent condition for reciprocity in case of transmission parameter and hybrid parameter respectively and similarly S_{T}, S_{h} represent condition for symmetry in case of transmission parameter and hybrid parameter respectively then match the following : (1) R_{T} (a) A = D (2) R_{h} (b) h_{12} = h_{21} (3) S_{T} (c) AD - BC = 1 (4) S_{h} (d) h_{12} = - h_{21} (e) B = c (f) Δh = 1

The Nyquist plot of a stable, transfer function G(s) is shown in the figure. We are interested in the stability of the closed loop system in the feedback configuration shown.

The gain and phase margins of G(s) for closed loop stability are