Final Answer
Silicon is the most abundant cation in the continental crust. so the correct option is d)silicon.
Step-by-step explanation:
Cation in the Continental Crust: The question focuses on the most abundant cation in the continental crust. The continental crust is primarily composed of various elements.
Identification of the Correct Element: To determine the correct answer, we need to consider the elements mentioned in the options: aluminum, iron, oxygen, and silicon.
Composition of Continental Crust:
The continental crust is made up of granitic rocks. This is a crucial aspect as it distinguishes the continental crust from the oceanic crust, which is predominantly composed of basaltic rocks. The granitic composition imparts specific characteristics to the continental crust.
Selection of the Correct Option: Silicon is the most abundant cation in the continental crust, making option (d) silicon the correct answer.