If due to the oxide fixed charge the c-v curve is shifted

Question

Consider the C-V curve of an MOS capacitor in Fig. 5-38 (the solid line). The capacitor area is 6.400 µm². C₀ = 45 pF and C₁ = 5.6 pF.

If, due to the oxide fixed charge. the C-V curve is shifted from the solid line to the dashed line with ?V = 0.05 V. what is the charge polarity and the area density (C/cm²) of the oxide fixed charge?