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.

Problem: eddy and freddy start simultaneously from city a and they travel to city b and city c respectively. eddy takes 3 hours and freddy takes 4 hours to complete the journey. if the distance between city a and city b is 510 kms and city a and city c is 300 kms. what is the ratio of their average speed of travel ? ( eddy: freddy )
Options: a. 8 / 3, b. 3 / 8, c. 8 / 5, d. 5 / 8, e. 34 / 15
e