Task: Question Answering
Input (English): Question: If 1/a^2 + a^2 represents the diameter of circle O and 1/a + 2a = 3, which of the following best approximates the circumference of circle O?

 Option A: 28

 Option B: 22

 Option C: 20

 Option D: 16

 Option E: 12
Output (English): Option D