A typical basalt consists of approximately 50%

Correct option is D

Explanation:
Basalt is a mafic igneous rock that is rich in magnesium and iron and has moderate silica content. The silica (SiO₂) content in typical basalt ranges between 45% and 52%, which makes this the dominant component among the listed options. While other oxides such as Al₂O₃, FeO, and CaO are present, their concentrations are significantly lower than SiO₂.
Information Booster:
Basalt is commonly found in oceanic crust and volcanic regions. Its composition includes:
· SiO₂: ~50%
· Al₂O₃: ~13-16%
· FeO/Fe₂O₃: ~8-12%
· CaO: ~10%
· MgO, Na₂O, K₂O: in smaller percentages Silica content helps classify igneous rocks: felsic (>65%), intermediate (55-65%), mafic (45-55%), and ultramafic (<45%). Basalt falls into the mafic category due to its ~50% silica.