The next time Mr. Hon purchases a new car will be in 4 years. Likewise, the next time Ms. Jasper purchases a new car will be in 6 years. The question is asking when they will both purchase new cars in the same year.
One way to find the answer is to find the least common multiple of 4 and 6. The multiples of 4 are: 4, 8, 12, 16, 20, 24... The multiples of 6 are: 6, 12, 18, 24...
From the lists above, we see that the least common multiple of 4 and 6 is 12. Therefore, Mr. Hon and Ms. Jasper will next purchase new cars in the same year 12 years from now.
The answer is C. in 12 years.