Correct Answer: IHJI

Solution : Given:
H_JH_IJHHI_HH_JH

To fill the series we have to divide the series – H_JH / _IJH / HI_H / H_JH
Let's check each option –
First option: IHJI; H I JH / H IJH / HI J H / H I JH (HIJH is repeated in the series.)
Second option: HIHI; H H JH / I IJH / HI H H / H I JH (No repeated pattern has been found.)
Third option: IHIJ; H I JH / H IJH / HI I H / H J JH (No repeated pattern has been found.)
Fourth option: HJHJ; H H JH / J IJH / HI H H / H J JH (No repeated pattern has been found.)

So, the series becomes→HIJHHIJHHIJHHIJH. Hence, the first option is correct.