You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

Which is the best example of evaporation?  
 (A) raindrops freezing (B) an ice cube melting (C) a puddle drying in the sun (D) a sponge soaking up water
C

Rocks are classified as igneous, metamorphic, or sedimentary according to  
 (A) their color (B) their shape (C) how they formed (D) the minerals they contain
C

Choose the investigation that would best answer the question: Does the length of a string change how fast a pendulum swings?  
 (A) Tie identical weights to two strings of different lengths. (B) Tie two different weights to a string. (C) Tie identical weights to a long string. (D) Tie two different weights to two identical strings.

A