Q: 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: in a group of 150 readers who read science fiction or literacy works or both, 120 read science fiction and 90 read literacy works. how many read both science fiction and literacy works ?
Options: a. 70, b. 60, c. 90, d. 100, e. 110
A:
b