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: what is the smallest integer that is multiple of 5, 711
Options: a. a. 70, b. b. 35, c. c. 385, d. d. 280, e. e. 140
c

Problem: a can give b 100 meters start and c 200 meters start in a kilometer race. how much start can b give c in a kilometer race ?
Options: a. 111.12 m, b. 221.12 m, c. 271.12 m, d. 611.12 m, e. 191.12 m
a

Problem: the ratio between the present ages of a and b is 3.5: 3 respectively. the ratio between a ' s age 4 years ago and b ' s age 4 years hence is 1: 1. what is the ratio between a ' s age 4 years hence and b ' s age 4 years ago ?
Options: a. 14: 4, b. 13: 0, c. 15: 11, d. 13: 12, e. 13: 17

c