Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.
Example: Problem: a multiple choice test consists of 4 questions, and each question has 5 answer choices. in how many r ways can the test be completed if every question is unanswered ?
Options: a. 24, b. 120, c. 625, d. 720, e. 1024
Example solution: c
Example explanation: 5 choices for each of the 4 questions, thus total r of 5 * 5 * 5 * 5 = 5 ^ 4 = 625 ways to answer all of them. Hence, the answer is c.

Problem: Problem: a salesman sold twice as much pears in the afternoon than in the morning. if he sold $ 510 kilograms of pears that day, how many kilograms did he sell in the afternoon ?
Options: a. 120, b. 180, c. 340, d. 280, e. 320

Solution: c