The correct option is D A>C>B
The more the number of p orbitals involved in hybridisation, the more is the p-character of the hybrid orbital and hence, more is the p-character of the bonds. The hybridisations are:
SiO2 is sp3 hybridised with 3 p-orbitals involved. CO2 is sp hybridised with 1 p-orbital involved. Graphite is sp2 hybridised with 2 p-orbitals involved. Hence, p character is maximum in SiO2, then graphite, and the least in CO2.