The correct answer is A. Quartz.
Quartz is the most abundant mineral in granite, making up about 50% of its volume. It is a hard, brittle mineral that is resistant to weathering and erosion. This makes it an important component of granite’s strength.
Felspar is the second most abundant mineral in granite, making up about 30% of its volume. It is a feldspar, which is a group of minerals that are composed of aluminum, silicon, oxygen, and potassium, sodium, or calcium. Feldspars are relatively soft and easily weathered, which makes them less important for granite’s strength.
Mica is a group of minerals that are composed of silicon, oxygen, aluminum, and potassium. Micas are relatively soft and easily weathered, which makes them less important for granite’s strength.
Therefore, the predominant constituent which is responsible for strength in granite is quartz.