Correct Answer: INVENTIVE

Solution : Given:
INQUISITIVENESS

Let's compare all the options —

First option: QUITS
All the letters of QUITS are present in the word INQUISITIVENESS.

Second option: QUIETNESS
All the letters of QUIETNESS are present in the word INQUISITIVENESS.

Third option: INVENTI V E
Two V's are not present in the word INQUISITIVENESS. Hence, it's the odd one out.

Fourth option: QUININE
All the letters of QUININE are present in the word INQUISITIVENESS.

Hence, the third option is correct.