Correct Answer:
A. She is smarter of the two sisters.
When comparing two items or people, the comparative degree of an adjective should be used. The superlative degree is reserved for comparing three or more.
- A: She is smarter of the two sisters. This is the correct sentence. "Smarter" is the comparative form of "smart," which is appropriate when comparing exactly two individuals. The phrase "of the two" clearly indicates this comparison.
- B: She is the smartest among the two. This is incorrect. "Smartest" is the superlative form, used for three or more. Additionally, "among the two" is less idiomatic than "of the two."
- C: She is smarter than the two sisters. While grammatically correct, "smarter than the two sisters" implies she is smarter than the group as a whole, rather than being the smarter individual *out of* the two. "Smarter of the two" is more precise for selecting one from a pair.
- D: She is more smart of the two. This is incorrect. For single-syllable adjectives like "smart," the -er ending (smarter) is preferred over "more smart."