Explanation:

Correct option:4

Let's check each pair of adjoining numbers in the sequence:

Sequence: 8 9 6 7 3 9 3 7 8 3 9 9 5 6 3 9 6 9 3 9 8 

8+9 = 17

9+6 = 15

6+7 = 13

7+3 = 10

3+9 = 12 (Pair 1)

9+3 = 12 (Pair 2)

3+7 = 10

7+8 = 15

8+3 = 11

3+9 = 12 (Pair 3)

9+9 = 18

9+5 = 14

5+6 = 11

6+3 = 9

3+9 = 12 (Pair 4)

9+6 = 15

6+9 = 15

9+3 = 12 (Pair 5)

3+9 = 12 (Pair 6)

9+8 = 17

 There are 6 pairs of adjoining numbers that add up to 12.

8 9 6 7 3 9 3 7 8 3 9 9 5 6 3 9 6 9 3 9 8

Hence 6 pairs is the correct answer