Time variability of the optical flux and X-ray properties of Mon-771 with the panel format and content as in Fig. 4. Contour levels in the C-stat space corresponding to the 68%, 90%, and 99% statistical confidence regions from the fit of the X-ray spectrum of Mon-771 observed during the time interval #6 (black contours) are compared to that obtained from the average spectrum observed during the remaining intervals (excluding the flare, red contours). The cross marks the values obtained from the best fit.