In the following series of numbers, find out how many times 1,3, and 7 have appeared together, 7 being in the middle, 1 and 3 on either side of 7?297 3 1 7 3 7 7 1 3 3 1 7 3 8 5 7 1 3 7 7 1

• A. 2
• B. 4
• C. 5
• D. more than 5