Select the option that represents the letters that, when placed from left to right in the blanks, will complete the letter series.
P _ G I O _ D _ I O R D G _ O _ D G I O

Correct option is B

Given P _ G I O _ D _ I O R D G _ O _ D G I O
From option (b) DQGIS
P D G I O/ Q D G I O / R D G I O / S D G I O
In this series P → Q → R → S are increasing alphabet remaining letters are same.
Therefore, the correct answer is (b).