Correct Answer - Option 4 : pppo
The given series:
oo_ooo_oooo _oooo_p
On replacing 'pooo' in blanks, we get:
oopoooooooooooooop (no pattern)
On replacing 'ppoo' in blanks, we get:
oopooopoooooooooop (no pattern)
On replacing 'pppp' in blanks, we get:
oopooopoooopoooopp
On replacing 'pppo' in blanks, we get:
oop ooop oooop ooooop (pattern)
Hence, we need to replace the blanks with 'pppo' to complete the series.