Geometry

Question Analysis
This question involves sampling methods and representativeness.
The main focus is to identify a stratified sampling approach that accounts for grade-level subgroups.

Key Concept Explanation
Stratified Sampling: Divides the population into subgroups (strata, e.g., grades) and samples proportionally from each to ensure representation.
Random Sampling (A): Unbiased but may not guarantee proportional representation of each grade.
Convenience/Voluntary Sampling (B, D): Prone to bias (e.g., only certain students participate).

Step-by-Step Solution
The population is divided into 4 grades (9–12), each with 250 students.
To ensure each grade is represented, strat...