Detailed Instructions: You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.
Q: Question: Lamp A flashes every 6 seconds, Lamp B flashes every 8 seconds, Lamp C flashes every 10 seconds. At a certain instant of time all three lamps flash simultaneously. During the period of 4 minutes after that how many times will exactly two lamps flash? (Please include any flash of exactly two lights which occurs at the 4 minute mark.)

Option A: 16

Option B: 17

Option C: 18

Option D: 19

Option E: 20
A:
Option C