Explanation:

Option 1: Pyroxenes—These are important minerals in the Earth's mantle and oceanic crust but they're not the main players in the continental crust.

Option 2: Quartz—Sure, there's a lot of quartz in rocks like granite, but it's not the most abundant mineral overall.

Option 3: Feldspar— Here's the thing: feldspar is the heavy hitter. It makes up over half the continental crust, found in both plagioclase and orthoclase varieties.

Option 4: Micas—These give rocks a nice sparkle, but they're present in much smaller amounts compared to feldspar and quartz.

So, Option 3: Feldspar is absolutely the correct answer.