In a spectrometer experiment three prisms $A,\;B$ and $C$ with same angle of prism but of different materials of refractive indices $\mu_A = 1.33, \; \mu_B = 1.55, \; \mu_C = 1.44$ are used. The corresponding angles of minimum deviation $D_A,\;D_B,\;D_C$ measured will be such that :