The answer is $\boxed{\text{(E) 11, 8}}$.
In this sequence, each number is repeated, then 3 is subtracted to get the next number. So, the next pair of numbers is $\boxed{\text{11, 8}}$.
Here is a table showing the sequence:
Number | Repeated | Subtract 3 | Next number
——- | ——– | ——– | ——–
20 | 20 | -3 | 17
17 | 17 | -3 | 14
14 | 14 | -3 | 11
11 | 11 | -3 | 8
Option A is incorrect because 8 is not repeated in the sequence.
Option B is incorrect because 11 is repeated in the sequence, but 11 is not followed by 11.
Option C is incorrect because 11 is followed by 8, not 14.
Option D is incorrect because 8 is followed by 11, not 9.