Detailed Instructions: 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.
Q: Problem: the cost of registration at a professional association meeting was $ 50 per person; a lunch for registrants only was available for an additional $ 22 per person. if the number of registrants who paid for lunch was 10 more than the number who did not, and if receipts for registration and lunch totaled $ 61720, how many people paid just for registration at the meeting ?
Options: a. 700, b. 800, c. 1,300, d. 500, e. 1,800
A:
d