Task: Question Answering
Input (English): For any positive integer [n] represents the sum of the integers from 1 to n. For example, [5] = 1 + 2 + 3 + 4 + 5 = 15. Which of the following is equal to [10] - [9] ?
(A)[1] (B)[2] (C)[3] (D)[4] (E)[5]
Output (English): D