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: a train traveled the first d miles of its journey it an average speed of 50 miles per hour, the next d miles of its journey at an average speed of y miles per hour, and the final d miles of its journey at an average speed of 160 miles per hour. if the train ’ s average speed over the total distance was 96 miles per hour, what is the value of y ?
Options: a. 68, b. 84, c. 90, d. 120, e. 160
e

Problem: a rhombus has area 432 sq m, one diagonal is 36 cm. find other diagonal ?
Options: ['a. 2400 m', 'b. 2500 m', 'c. 2600 m', 'd. 2700 m', 'e. 2900 m']
a

Problem: a technician makes a round - trip to and from a certain service center by the same route. if the technician completes the drive to the center and then completes 50 percent of the drive from the center, what percent of the round - trip has the technician completed ?
Options: a. 70, b. 65, c. 60, d. 75, e. 80

d