Inbred lines of animals, such as laboratory mice, are useful for studying complex traits because:
A)individuals are genetically identical, so differences in traits must be due to environmental differences. B)although individuals differ both genetically and environmentally, the genetic differences are known, so differences in traits can be understood. C)animals are kept in identical environments, so any differences in traits are due to differences in their genes. D)both genetic and environmental differences between individuals are known, making differences in their traits easy to understand. E)None of the answer options is correct.