Answer:
C. August's mouth goes straight across when he smiles.
Step-by-step explanation:
We are looking for a specific description of what August looks like. Just knowing that August smiled isn't doing us any good here because everyone smiles differently, how can we get an accurate pictures of August's smile in our head if there's so many variations of smiles?
This means we can cross out the first two choices since they don't provide much information about what August looks like. When comparing choice C and choice D, we see that C specifically explained that August's smile looks like his mouth just goes in a straight line, which paints a very specific image in our heads. Choice D talks about a feeling of almost laughing, but feelings aren't a physical feature so we can't really visualize it. This is way C is the best answer.