Correct Answer: THERMAL

Solution : Given:
GRANDMOTHER

Now, let's compare all the option words with the word GRANDMOTHER –
First option: TREND; All the letters of TREND are present in the word GRANDMOTHER.
Second option: THERMAL; L is not present in the word GRANDMOTHER. Therefore, all the letters of THERMAL are not present in the word GRANDMOTHER.
Third option: MODERN; All the letters of MODERN are present in the word GRANDMOTHER.
Fourth option: RANDOM; All the letters of RANDOM are present in the word GRANDMOTHER.

So, from the above, only THERMAL cannot be formed from the word GRANDMOTHER. Hence, the second option is correct.