The red leaves do contain the same amount of chlorphyll. The color of the leaves is due to the abundance of any particular pigment.
I believe the correct answer is A. gabbro is made out of several minerals. Given that its composition is not simple, because it consists of several various minerals, it cannot be called a mineral, but rather a rock. It consists of minerals such as feldspars, pyroxene, and olivine.
Hope this helps!