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 box contains 100 balls, numbered from 1 to 100. if 3 balls are selected at random and with replacement from the box. if the 3 numbers on the balls selected contain two odd and one even. what is the probability r that the first ball picked up is odd numbered ?
Options: a. 0, b. 1 / 3, c. 1 / 2, d. 2 / 3, e. 1
d