Correct Answer: HJMW

Solution : Given:
FLG_K_JMPH_RUFP_

To fill the series we have to divide the series – FLG_ / K_JM / PH_R / UFP_
Let's check each option –
First option: GHMX; FLG G / K H JM / PH M R / UFP X (No repeated pattern has been found. )
Second option: OWMO; FLG O / K W JM / PH M R / UFP O (No repeated pattern has been found.)
Third option: HJMW; FLG H / K J JM / PH M R / UFP W (Add 5 to the place value of the first letter, subtract 2 from the place value of the second letter, add 3 to the place value of the third letter, and add 5 to the place value of the fourth letter.)
First letter of the series→F + 5 = K; K + 5 = P; P + 5 = U
Second letter of the series→L – 2 = J; J – 2 = H; H – 2 = F
Third letter of the series→G + 3 = J; J + 3 = M; M + 3 = P
Fourth letter of the series→H + 5 = M; M + 5 = R; R + 5 = W
Fourth option: ABDG; FLG A / K B JM / PH D R / UFP G (No repeated pattern has been found.)

So, the series becomes FLGHKJJMPHMRUFPW. Hence, the third option is correct.