Concept:Correct sentence structure requires a logical subject-verb-object order and clear meaning.
Explanation:Option 1: "Teachers eager to learn" wrongly describes teachers as keen to learn, not students. So it is incorrect.
Option 2: "Students eager to learn are a delight for their teachers" follows the pattern: subject (students) + adjective phrase + verb + object. The meaning is logical. This is the correct structure.
Option 3: The words are jumbled; the phrase "for their teachers eager to learn" is misplaced. Thus it is wrong.
Option 4: "Teachers eager to learn" again misplaces the eager quality. The intended meaning is opposite. So it is incorrect.
Therefore, only option 2 has both correct grammar and proper context.
Answer:Option B (Students eager to learn are a delight for their teachers)