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: Melissa is creating a new product to quench people's thirst. She thinks it will be more popular if it is less flat. She decides to (A) add more salt to the drink (B) add some dissolved carbon dioxide (C) shake up the drink bottles before shipping them to the stores (D) boil the drink in a large vat
Output:
B