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: the marks obtained by vijay and amith are in the ratio 4: 5 and those obtained by amith and abhishek in the ratio of 3: 4. the marks obtained by vijay and abhishek are in the ratio of ?
Options: a. 3: 4, b. 3: 5, c. 6: 5, d. 3: 6, e. 3: 8

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Solution: b