Explanation:

In this formation, the first number in the first column is getting multiplied by the number in the third column and the resultant number is being added to the number in the second column to give the number in the fourth column.

First row 6 × 2 + 8 = 20,
Second row 7 × 4 + 2 = 30,
Fourth row 5 × 9 + 5 = 50
Therefore, third row 8 × 6 + 7 = 55,
Hence, option A is correct.