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.

[Q]: In humans, B is the allele for brown eyes and b is the allele for blue eyes. Two brothers both have brown eyes, but one of them has both the B and b alleles while the other only has B alleles. Which statement is true about the brothers?  
 (A) They have the same genotype and phenotype. (B) They have different phenotypes and genotypes. (C) They have the same phenotype but different genotypes. (D) They have the same genotype but different phenotypes.
[A]: C


[Q]: Campers shouted toward a canyon wall. What characteristic of sound best explains why the campers heard an echo?  
 (A) Sound waves traveled slowly down the canyon. (B) Sound waves were absorbed by the canyon wall. (C) Sound waves reflected off the canyon wall. (D) Sound waves were refracted around the canyon.
[A]: C


[Q]: When a tree suffers from a decreased ability to transport materials within the phloem, what is directly impacted?  
 (A) volume of water in the xylem (B) flow of necessary nutrients (C) response to environmental factors (D) rate of photosynthesis in leaves
[A]:
B