Which of the following is not an isotope of

Read the following information carefully and answer the question that follows. You must assume everything in the information to be true.

In the following question, select the related letter pair from the given alternatives. 

ER : ET :: ? 

Select the option that is related to the third number in the same way as the second number is related to the first number.

576:384 ∷ 765: ?

Direction: In each of the following questions, a series is given, with one term missing.

The position of how many letters will remain unchanged if each of the letter in the word ‘JANITOR’ is arranged in English alphabetical order?

‘Entertainment’ is related to ‘Television’ in the same way as ‘Warmth’ is related to ‘______’.

Select the word that can be formed using the letters of the given word only as many times as the letters have been used in the word.

Select the set of numbers from the given options, which is similar to the given set.

(17, 39, 11)