Definition: In this task, you are given a multiple-choice question and you have to pick the correct option. Answer with option indexes (i.e., "A", "B", "C", and "D").
Input: A pot of cold water, with heat now applied, may be noted to have reached its boiling point when (A) bubbles are seen (B) food is cold (C) water is warm (D) salt is added
Output:
A