Correct Answer: PRONE

Solution : Given:
PHOTOSYNTHETIC

Now, let's compare all the option words with the word PHOTOSYNTHETIC –
First option: THOSE; All the letters of the word THOSE are present in the word PHOTOSYNTHETIC.
Second option: SCENT; All the letters of the word SCENT are present in the word PHOTOSYNTHETIC.
Third option: PRONE; All the letters of the word PRONE are not present in the word PHOTOSYNTHETIC. R is not present in the word PHOTOSYNTHETIC.
Fourth option: COTTON; All the letters of the word COTTON are present in the word PHOTOSYNTHETIC.

Therefore, PRONE cannot be formed from the word PHOTOSYNTHETIC. Hence, the third option is correct.