Concept:The task checks concept understanding and builds mathematical communication skills.
Explanation:The teacher asks students to explain area and perimeter in a letter to an absent friend.
This shows the teacher how well the student grasps the two concepts.
It also improves the student’s ability to express mathematical ideas clearly.
Option (i) is correct because the teacher learns the student's understanding.
Option (iv) is correct because the student practices mathematical communication.
Option (ii) is not the main purpose; the task is not primarily to help the absentee.
Option (iii) is not the goal; letter‑writing is just a tool for the math task.
Answer:C. (i), (iv)