Concept:Granitic rocks are felsic igneous rocks that are rich in silica and aluminium.Explanation:Granite forms when molten magma cools slowly underground.Its chief minerals are quartz and feldspar.Quartz contains silica (SiO2), while feldspar is rich in both silica and aluminium.Thus, granitic rocks are characterised by a high content of silica and aluminium.Answer:A. silica and aluminium